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Gray Man #16

Dark Union

Not yet published
Expected 16 Feb 27
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A ghost from Court’s past challenges everything the Gray Man believes in this latest electrifying entry in the #1 New York Times bestselling series.

Court Gentry is the last surviving member of his family. His brother, Chance, was a police officer who lost his life years ago in a line of duty shooting. So how is it possible that Court catches a glimpse of his brother at their father’s funeral?

It’s this shocking development that sends Court on a quest for the truth and a search for his missing sibling. But the dark state will do anything to keep its secrets.

496 pages, Hardcover

Expected publication February 16, 2027

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About the author

Mark Greaney

67 books6,655 followers
Mark Greaney has a degree in International Relations and Political Science. In researching The Gray Man series he traveled to ten countries and trained extensively in the use of firearms, battlefield medicine, and close range combative tactics.

Learn more at MARKGREANEYBOOKS.COM

Email Mark at MarkGreaneyBooks@gmail.com


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Displaying 1 - 5 of 5 reviews
Profile Image for Ryan Davison.
461 reviews47 followers
Review of advance copy received from NetGalley
October 27, 2026
A prologue from 1865 sets up an intriguing premise in the opening pages of Dark Union. What if a small team established after the Civil War charged with handling rule breakers outside of the U.S. government, still existed 162 years later? Well, they do indeed, and the group, Dark Union, functions now in a similar fashion to when it began.

Jump to 2027, and an insidious company by the name of Gauntlet has a Special Operations Unit taking out U.S. CIA agents at an alarming rate. Now they are hunting Catherine King, a reporter writing a tell-all book about the company. She is in grave danger, but her protector, Courtland Gentry, known as the Gray Man, might be the single most lethal human on Earth. He works for an off-the-books intelligence shop known as Ghost Town, and he and his team protect the reporter.

As Courtland (Court) runs around protecting Catherine, the plot is peeled back to expose Court’s brother, Chancellor (Chance), a man presumed dead for seven years, working as an assassin for Dark Union - the group that formed in 1865. After a slick scene where Chance takes down an Italian killer who orchestrated many of the CIA attacks, he becomes suspicious of his masters. So, one Gentry brother digs into an evil group, protects a journalist, and kills people, while the other brother digs into his own group, protects himself, and kills people. Ah, genetics are fun.

There is plenty to be impressed by: wingsuit flyers, stopgap houses, microdrones, and high-tech weaponry galore. Sharply composed extended action scenes are a challenge to choreograph, but this author accomplishes them with creative flourish. But still, 500 pages feels long for an action book.

If you enjoy blood-soaked, action-packed novels, with characters constantly referred to as “assets” and everyone responding to a cheesy code name, you’ll dive into this with relish. It can take a little getting used to, but there are some genuinely fun set pieces even if these types of novels lack depth. In terms of pure plotting, this feels like it would be near the top of the action-adventure genre.

Dark Union is the 16th in the series, but this reader’s first. It worked perfectly fine as a standalone.

Thanks to NetGalley and Berkeley Publishing for a review copy.
Profile Image for Suzanne.
1,955 reviews44 followers
Review of advance copy received from NetGalley
October 17, 2026
For Gray Man fans, DARK UNION provides the conclusion to much of the action in the preceding novel, THE HARD LINE. We learn more about the roles of various government figures and nefarious foreign operators. And we finally meet one missing member of Court Gentry’s family of origin, his brother, Chance, long presumed dead. Mark Greaney weaves distinct geopolitical threads together and arrives at a fascinating place, filled with intrepid journalists, competing secret organizations and many of our returning favorite characters. The returning characters of the series were badly injured at the end of the last book. And it’s payback time. This installment continues the joyride of reading this series. I received my copy from the publisher through NetGalley.
Profile Image for Plunkemus Prime.
37 reviews
Review of advance copy received from NetGalley
October 26, 2026
I received an ARC from NetGalley in exchange for an unbiased review.

There is no slow pace when it comes to Court Gentry aka Six aka Violator aka The Gray Man.

Book #16 picks up right where The Hard Line left off. Court last saw someone from his past at his father's funeral. Someone who he hasn't seen since he was in prison as a teenager and he has since thought dead. How is this person alive? What are they doing now? Did he really see them?

The Gauntlet Group is still terrorizing the intelligence community and has no plans to slow down as they work with international enemies to undermine United States Security. Can Court and the rest of Ghost Town actually stop them this time? Maybe, there might be some other black group that has been around for over a century that works to protect the country involved. Everything combined takes the reader on another wild ride.

If you have enjoyed the Gray Man books, you will get much of the same ride. So much has gone on that the book might not be for the casual reader. If you are into Mitch Rapp, Scot Harvath, and others---the Gray Man series might take over as your favorite thriller/spec-ops book series! Each book is fast paced, relevant with world problems, and never lets the reader down.

Mark Greaney is amazing for the research he does and is highly knowledgeable. He travels to research all his books and learns/trains with all types of firearms. I got him though in one spot---Yuengling Beer. Shot Show is mentioned in this book and one of the characters is getting a Yuengling beer from a casino bar. Yuengling doesn't distribute to Vegas or NV--I would know because i would be drinking it on all my trips there! I kid though, his research in the writing process is top notch and makes for excellent reading.
12 reviews
Review of advance copy received from NetGalley
October 19, 2026
What a wild ride!

Courts brother is alive. We are introduced to Chance Gentry, he is a member of the group Cold Harbor, it's an assassination group dating back to the 1800's. He is tasked with eliminating a man with the code name Masquerade.

Court is working along with a reporter named Catherine King, they are working to find out information on the Gauntlet Group. Trying to expose them, they have been tied to the killing of government officials.

It turns out Masquerade was hired by the Gauntlet Group to kill the deputy director of the CIA.

The Gauntlet Group needs to tie up loose ends. Not only with Masquerade and Cold Harbor. They also plan to go after Ghost Town, who Court works for.

This book is great, if you follow Mark on Instagram.. You will see he travels the world and researches locations for these books. It really shows through in the writing. He transports you to a location. He may be one of the thriller writers who keeps getting better with every book.


217 reviews2 followers
Review of advance copy received from Netgalley
October 27, 2026
Absolutely the best movie I've ever read. Constant action from the first word, don't blink sneeze or cough. This book might just keep you awake at night. The story picks up where Hardline leaves off so my recommendation is read Hardline first. The book reads like military fiction meets historical fiction, or Tom Clancy meets Steve Berry. I can say no more for now, still catching my breath... Thanks to Netgalley and Berkley Publishing for an advanced copy in exchange for an honest review.
Displaying 1 - 5 of 5 reviews