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The Umbra Signal
When a mysterious transmission from a distant galaxy interrupts a routine night at a SETI lab, ex-Air Force analyst Liam Mills finds himself caught in a labyrinth of ancient codes, buried Cold War secrets, and a pattern that shouldn’t exist.
As the signal deepens in complexity, so does its grip on reality itself. Joined by a linguist haunted by loss, a rabbi obsessed with meaning, and a conspiracy-hardened engineer, Liam must untangle a cipher that blends language, memory, and spacetime, a cipher that seems to know them better than they know themselves.
But the more they decode, the more reality unravels. Time distorts. Memories fracture. And someone, or something, is watching.
The Umbra Signal is the first novel in a groundbreaking new Cipherlock™ Thriller, where code is prophecy, time is a weapon, and nothing stays buried forever.
As the signal deepens in complexity, so does its grip on reality itself. Joined by a linguist haunted by loss, a rabbi obsessed with meaning, and a conspiracy-hardened engineer, Liam must untangle a cipher that blends language, memory, and spacetime, a cipher that seems to know them better than they know themselves.
But the more they decode, the more reality unravels. Time distorts. Memories fracture. And someone, or something, is watching.
The Umbra Signal is the first novel in a groundbreaking new Cipherlock™ Thriller, where code is prophecy, time is a weapon, and nothing stays buried forever.
584 pages, Kindle Edition
Published July 31, 2025
31 people are currently reading
756 people want to read
About the author
David Williams
1 book7 followersSelected scene shorts are on YouTube @CipherlockPress:
https://www.youtube.com/@CipherLockPr...
Thrilled to share that The Umbra Signal was named a
2025 American Writing Awards Finalist — Science Fiction.
Thrilled to share that The Umbra Signal received a ⭐⭐⭐⭐⭐ MUST READ
review on Reedsy Discovery!
“The Matrix meets The Da Vinci Code with a tip of the hat to James Joyce.
Exercise for your little grey cells.” — Gordon A. Long, Reedsy Discovery
https://reedsy.com/discovery/best-sci...
https://www.youtube.com/@CipherLockPr...
Thrilled to share that The Umbra Signal was named a
2025 American Writing Awards Finalist — Science Fiction.
Thrilled to share that The Umbra Signal received a ⭐⭐⭐⭐⭐ MUST READ
review on Reedsy Discovery!
“The Matrix meets The Da Vinci Code with a tip of the hat to James Joyce.
Exercise for your little grey cells.” — Gordon A. Long, Reedsy Discovery
https://reedsy.com/discovery/best-sci...
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Displaying 1 - 11 of 11 reviews
September 14, 2025
David Williams’s The Umbra Signal is an intricate fusion of speculative science, Cold War intrigue, and emotional resonance. At its core lies Liam Mills, a former Air Force codebreaker whose encounter with a mysterious extra-terrestrial transmission propels him into a labyrinth of cryptography, memory, and fractured time.
What distinguishes Williams’s work is its structural daring. Chapters unfold like pieces of a cipher, demanding that readers assemble meaning much as the characters do. This fragmented form enhances the novel’s central theme: that knowledge is never handed down whole but uncovered through patience, interpretation, and risk. Far from a gimmick, this structure deepens the reading experience, placing the audience inside the puzzle rather than observing from the outside.
The novel balances intellectual rigor with emotional depth. Mills is not simply a vessel for scientific speculation; he is a man haunted by loss, and his vulnerability keeps the story grounded even as it veers into questions of time, causality, and the boundaries of perception. Williams’s secondary characters—scientists, linguists, skeptics—add dimension, each wrestling with their own fragile grasp on certainty.
If the novel occasionally lingers in technical speculation, its prose and pacing ensure the tension never fully dissipates. Williams understands that the true weight of discovery lies not in data alone, but in its human cost.
Ultimately, The Umbra Signal is both a page-turning thriller and a meditation on how we confront the unknown—within the cosmos and within ourselves. It rewards patient readers with a narrative that is as thought-provoking as it is immersive. For those seeking science fiction that challenges as much as it entertains, this is an exceptional beginning to a writer worth watching.
What distinguishes Williams’s work is its structural daring. Chapters unfold like pieces of a cipher, demanding that readers assemble meaning much as the characters do. This fragmented form enhances the novel’s central theme: that knowledge is never handed down whole but uncovered through patience, interpretation, and risk. Far from a gimmick, this structure deepens the reading experience, placing the audience inside the puzzle rather than observing from the outside.
The novel balances intellectual rigor with emotional depth. Mills is not simply a vessel for scientific speculation; he is a man haunted by loss, and his vulnerability keeps the story grounded even as it veers into questions of time, causality, and the boundaries of perception. Williams’s secondary characters—scientists, linguists, skeptics—add dimension, each wrestling with their own fragile grasp on certainty.
If the novel occasionally lingers in technical speculation, its prose and pacing ensure the tension never fully dissipates. Williams understands that the true weight of discovery lies not in data alone, but in its human cost.
Ultimately, The Umbra Signal is both a page-turning thriller and a meditation on how we confront the unknown—within the cosmos and within ourselves. It rewards patient readers with a narrative that is as thought-provoking as it is immersive. For those seeking science fiction that challenges as much as it entertains, this is an exceptional beginning to a writer worth watching.
September 28, 2025
Book scenes on YouTube:
https://www.goodreads.com/videos/list...
Just got a 5-Star MUST READ from Reedsy:
https://reedsy.com/discovery/book/the...
Although The Umbra Signal is my debut novel, it comes from decades of lived experience in high-stakes, high-tech worlds; drawing on my background in military intelligence, top-secret operations, and advanced science and technology. That foundation allowed me to build a world where the science is plausible, the suspense is grounded, and the stakes feel real.
I’ve always believed the most compelling stories are about people, not just the events that happen to them. This book is filled with flawed, complex characters who wrestle with loyalty, fear, and the price of truth; because in real life, even heroes are messy.
What I’m most proud of is that The Umbra Signal delivers a layered mystery that plays out on both a human and cosmic scale. It’s a thinking-person’s sci-fi thriller; one where every code cracked and every decision made has emotional weight. If you love high-concept science fiction that still bleeds humanity, this is the ride I’ve been waiting years to share. Here's a recent comment:
“The Umbra Signal is an intriguing and complex work that challenges traditional storytelling. Thought-provoking and richly layered, it blends science fiction with psychological drama in a puzzle-like narrative of time, memory, and hidden truths. Not for those seeking a straightforward story, but for readers who relish piecing together clues and decoding deeper meanings, it is a fascinating read.” — The American Writing Awards
https://www.goodreads.com/videos/list...
Just got a 5-Star MUST READ from Reedsy:
https://reedsy.com/discovery/book/the...
Although The Umbra Signal is my debut novel, it comes from decades of lived experience in high-stakes, high-tech worlds; drawing on my background in military intelligence, top-secret operations, and advanced science and technology. That foundation allowed me to build a world where the science is plausible, the suspense is grounded, and the stakes feel real.
I’ve always believed the most compelling stories are about people, not just the events that happen to them. This book is filled with flawed, complex characters who wrestle with loyalty, fear, and the price of truth; because in real life, even heroes are messy.
What I’m most proud of is that The Umbra Signal delivers a layered mystery that plays out on both a human and cosmic scale. It’s a thinking-person’s sci-fi thriller; one where every code cracked and every decision made has emotional weight. If you love high-concept science fiction that still bleeds humanity, this is the ride I’ve been waiting years to share. Here's a recent comment:
“The Umbra Signal is an intriguing and complex work that challenges traditional storytelling. Thought-provoking and richly layered, it blends science fiction with psychological drama in a puzzle-like narrative of time, memory, and hidden truths. Not for those seeking a straightforward story, but for readers who relish piecing together clues and decoding deeper meanings, it is a fascinating read.” — The American Writing Awards
September 16, 2025
The Umbra Signal, by David Williams, is about space, time, memories, history, and the future, all at the same time. I love science fiction and found this book so fascinating. Although there is the usual disclaimer that it is totally fictional, the science and computer language that is referred to throughout the book is very much based on reality. The book even contains a glossary giving the real world definitions of many of the terms used in the story (but it was at the end of the book so I didn’t know it was there until I had finished). This real life connection made reading the book take on a creepy feeling of “what if this kind of thing were true?” The end of the book could have been both the end and possibly the beginning all at the same time, which lent to that unsettling sense of could this be real.
Some of the terminology made it a bit harder to get through, and sometimes there were many things going on at once, so I was frequently confused as to what was happening. However, I found myself often caught up in the process and questioning the truth right along with the characters, and trying to guess the outcome. I would definitely recommend The Umbra Signal to anyone who likes science fiction, especially the kind that has such a close connection to reality.
Some of the terminology made it a bit harder to get through, and sometimes there were many things going on at once, so I was frequently confused as to what was happening. However, I found myself often caught up in the process and questioning the truth right along with the characters, and trying to guess the outcome. I would definitely recommend The Umbra Signal to anyone who likes science fiction, especially the kind that has such a close connection to reality.
September 23, 2025
A must read! This entire book shackled my attention!
The title of David Williams’ book, “The Umbra Signal,” intrigued me so much I had to read it. Not only read it, but studied it and meditated on it. Each scene drew me deeper, and deeper into the people and the plot to the point where I could not put the book down for hours on end.
Being an Air Force communications and computer veteran myself, I was no stranger to the signals and coding aspects of this book. The other technical and scientific concepts to this masterpiece only enticed me to expand my own understanding of the universe. I can’t express enough how brilliant Mr. Williams incorporates so many disparate disciplines into one novel (i.e., AI, Astronomy, Computers, Encryption/Decryption, Language, Memory, Morse Code, Networking, Physics, etc.,). Some might consider this geekiness as noise to a perfectly good plot…but to me…it was like listening to the great composer of classical music balance melody, harmony, and rhythm together in their great symphonies!
So anticipating a sequel to this genius Sci-Fi thriller!
The title of David Williams’ book, “The Umbra Signal,” intrigued me so much I had to read it. Not only read it, but studied it and meditated on it. Each scene drew me deeper, and deeper into the people and the plot to the point where I could not put the book down for hours on end.
Being an Air Force communications and computer veteran myself, I was no stranger to the signals and coding aspects of this book. The other technical and scientific concepts to this masterpiece only enticed me to expand my own understanding of the universe. I can’t express enough how brilliant Mr. Williams incorporates so many disparate disciplines into one novel (i.e., AI, Astronomy, Computers, Encryption/Decryption, Language, Memory, Morse Code, Networking, Physics, etc.,). Some might consider this geekiness as noise to a perfectly good plot…but to me…it was like listening to the great composer of classical music balance melody, harmony, and rhythm together in their great symphonies!
So anticipating a sequel to this genius Sci-Fi thriller!
August 12, 2025
David Williams doesn’t just write a book—he decrypts reality itself. The Umbra Signal is not your typical sci-fi thriller. It starts in a dusty guard shack in 1955 Nevada, where a flicker of Morse code cracks open a story that stretches across decades and dimensions. With strange transmissions, Cold War secrets, and a spacecraft that seems less “alien” and more “misplaced,” this story grabs you by the collar and whispers, You’ve always felt something was off, haven’t you?
The story jumps through timelines—Area 51, Cold War backchannels, and a modern-day SETI lab—all stitched together with eerie precision. But instead of long exposition dumps, Williams uses short, punchy chapters labeled as Cipher, Lock, and Cipherlock—like puzzle pieces from a deeper, hidden history. Each scene hums with unease, like you're not just reading a mystery, you’re remembering it. The Morse code messages, time glitches, and vanishing soldiers aren’t just sci-fi ideas—they feel like echoes from something real and unfinished.
For those who love decoding cryptic clues, questioning official stories, or just want a thriller that doesn’t treat you like a passenger but a co-conspirator, The Umbra Signal delivers. It’s weird in all the best ways—part time-travel mystery, part alien-tech heist, and part emotional tribute to memory, grief, and gut instinct. You won’t just read this book. You’ll feel like it read you.
The story jumps through timelines—Area 51, Cold War backchannels, and a modern-day SETI lab—all stitched together with eerie precision. But instead of long exposition dumps, Williams uses short, punchy chapters labeled as Cipher, Lock, and Cipherlock—like puzzle pieces from a deeper, hidden history. Each scene hums with unease, like you're not just reading a mystery, you’re remembering it. The Morse code messages, time glitches, and vanishing soldiers aren’t just sci-fi ideas—they feel like echoes from something real and unfinished.
For those who love decoding cryptic clues, questioning official stories, or just want a thriller that doesn’t treat you like a passenger but a co-conspirator, The Umbra Signal delivers. It’s weird in all the best ways—part time-travel mystery, part alien-tech heist, and part emotional tribute to memory, grief, and gut instinct. You won’t just read this book. You’ll feel like it read you.
September 28, 2025
This novel is about the conspiracy theory to end all conspiracy theories. What if there really was a secret cabal controlling the world, but they lost control of the system, and it started controlling its creators? The only chance humans have to hold onto their past is wild-card unpredictable creativity. And the computer is rewriting a version of history with the heroes erased.
That synopsis gives you an idea of the depth and thoughtfulness of this book. The conflict continues on various levels, drawing from ancient mythology, various conspiracy theories and a healthy dose of modern computer philosophy. We (and the characters) are never sure whether the cryptic messages come from Andromeda, the invention of Samuel Morse or Jewish Kabbalah.
The writing style is seriously poetic, using powerful imagery and metaphor to draw readers into the experience. Thematically, the story discusses the possibility of the individual being able to make a free choice. The answer seems to be that life is a melody with the tune already written, but how the musicians play the music is up to them.
There is a lot of repetition in the dialogue, with the same ideas being tossed around in different forms. But we need it. As the characters gradually dig deeper into the programming of reality, they learn what’s going on, and readers do too.
The action sequences are scattered through the programming and discussion, but there is a key moment around page 400 where the heroes make a decision to start writing their own code, to jolt the computer into a reset. From this point the conflict is more clear to us, and the physical action picks up as well.
This book is not an easy read. It teems with esoteric discussion, but the intensity of the feelings of the wonderful characters carries us through. We progress more smoothly once we realize that it is not necessary to understand the complex ideas in detail; it is enough that the characters do. The reading experience is enhanced if we let the poetry carry us away, and we can ride on the emotions of the individuals to an ending that reaffirms the power of the creative human soul.
And if you finish the book and still want more of the discussion, read the appendix. Wow!
This review was originally published on Reedsy Discovery
That synopsis gives you an idea of the depth and thoughtfulness of this book. The conflict continues on various levels, drawing from ancient mythology, various conspiracy theories and a healthy dose of modern computer philosophy. We (and the characters) are never sure whether the cryptic messages come from Andromeda, the invention of Samuel Morse or Jewish Kabbalah.
The writing style is seriously poetic, using powerful imagery and metaphor to draw readers into the experience. Thematically, the story discusses the possibility of the individual being able to make a free choice. The answer seems to be that life is a melody with the tune already written, but how the musicians play the music is up to them.
There is a lot of repetition in the dialogue, with the same ideas being tossed around in different forms. But we need it. As the characters gradually dig deeper into the programming of reality, they learn what’s going on, and readers do too.
The action sequences are scattered through the programming and discussion, but there is a key moment around page 400 where the heroes make a decision to start writing their own code, to jolt the computer into a reset. From this point the conflict is more clear to us, and the physical action picks up as well.
This book is not an easy read. It teems with esoteric discussion, but the intensity of the feelings of the wonderful characters carries us through. We progress more smoothly once we realize that it is not necessary to understand the complex ideas in detail; it is enough that the characters do. The reading experience is enhanced if we let the poetry carry us away, and we can ride on the emotions of the individuals to an ending that reaffirms the power of the creative human soul.
And if you finish the book and still want more of the discussion, read the appendix. Wow!
This review was originally published on Reedsy Discovery
August 4, 2025
A fast-paced and engaging science fiction thriller that will stretch your mind and test the limits of your understanding about time, space, and history! As the story unfolds, you realize that what we think we know may not be true.
A small handful of mis-matched people with very special skills discover a radio signal that most others would have missed. The signal itself is highly significant, but enigmatic. As they work to verify where it came from, the mystery deepens - driving them far from the mainstream of science in pursuit of the truth… truth that others would prefer not be uncovered. Their commitment to discovering and sharing the truth may cause more problems than it solves.
This is a great read for those who love deep science and adventure in one package! The action spans continents; explores remote facilities filled with computers watching, listening, and calculating unknown formulas; contemplates undiscovered (or forgotten) technologies that may (or may not) be extraterrestrial; and delves deep into the ideas we think we know about the universe.
A sci fi / adventure masterpiece!
The cast of characters is a masterful blend of archetypes - each with their own background stories (and a few secrets) that provide context and depth to the storyline. The author does a great job of helping the reader to ‘see’, ‘hear’, and ‘feel’ each scene in the story. It does all this while moving at a pace that will keep you reading well past bedtime!
I highly recommend this to readers of all ages, but especially those of at least college age with some science background and an interest in exploring the boundaries of known science while wondering what mysteries still lie beyond our current understanding of the universe. It’s a fun ride from beginning to end, and when it’s over, you're still asking yourself, “What if…”?! I can’t wait for the next one!
A small handful of mis-matched people with very special skills discover a radio signal that most others would have missed. The signal itself is highly significant, but enigmatic. As they work to verify where it came from, the mystery deepens - driving them far from the mainstream of science in pursuit of the truth… truth that others would prefer not be uncovered. Their commitment to discovering and sharing the truth may cause more problems than it solves.
This is a great read for those who love deep science and adventure in one package! The action spans continents; explores remote facilities filled with computers watching, listening, and calculating unknown formulas; contemplates undiscovered (or forgotten) technologies that may (or may not) be extraterrestrial; and delves deep into the ideas we think we know about the universe.
A sci fi / adventure masterpiece!
The cast of characters is a masterful blend of archetypes - each with their own background stories (and a few secrets) that provide context and depth to the storyline. The author does a great job of helping the reader to ‘see’, ‘hear’, and ‘feel’ each scene in the story. It does all this while moving at a pace that will keep you reading well past bedtime!
I highly recommend this to readers of all ages, but especially those of at least college age with some science background and an interest in exploring the boundaries of known science while wondering what mysteries still lie beyond our current understanding of the universe. It’s a fun ride from beginning to end, and when it’s over, you're still asking yourself, “What if…”?! I can’t wait for the next one!
September 16, 2025
You don't have to be a sci-fi nerd to enjoy this book!
Although I'm an avid reader, my go-to reads are generally historical and contemporary fiction, mysteries, and romance. This isn't a book I would normally gravitate towards, but I'm so glad I picked it up! Even with some of the in-depth science and time "stuff" going a bit over my head, there was plenty of intrigue, suspense, and character development to keep me turning the pages. I felt as though I could see the scenes playing out in front of me as if I was watching a movie. Looking forward to book 2!
Although I'm an avid reader, my go-to reads are generally historical and contemporary fiction, mysteries, and romance. This isn't a book I would normally gravitate towards, but I'm so glad I picked it up! Even with some of the in-depth science and time "stuff" going a bit over my head, there was plenty of intrigue, suspense, and character development to keep me turning the pages. I felt as though I could see the scenes playing out in front of me as if I was watching a movie. Looking forward to book 2!
November 9, 2025
This book seems to draw a lot from Carl Sagan's "Contact" and the Wachowski Bros. "The Matrix", both of which I love! I wanted to love this book, but the back half left me feeling confused trying to understand what was happening. Mainly, I had a hard time believing how the AI was rewriting history, which really took me out of the story.
This entire review has been hidden because of spoilers.
August 3, 2025
A real page turner. Just enough "real science" to straddle the line between fiction and non-fiction. The characters are well formed and the book makes you really care about them. A fascinating subject.
August 3, 2025
A real page turner. Just enough "real science" to straddle the line between fiction and non-fiction. The characters are well formed and the book makes you really care about them. A fascinating subject.
Displaying 1 - 11 of 11 reviews