This Is Life: How the Science of the Cosmos Explains What We Are

by Christophe Galfard, Leighton Pugh (Narrator)

Embark on a breathtaking journey to uncover the secrets of life itself, from the author of the international bestseller, The Universe in Your Hand.

In this immersive and mind-expanding book, acclaimed physicist Christophe Galfard takes you on an adventure like no other to answer the fundamental what is life? You’ll travel back in time to witness the cataclysmic asteroid impact that doomed the dinosaurs, experience the tumultuous forces that shaped our planet, and discover how the first stirrings of life emerged from inanimate matter.

But your journey won’t end you’ll be shrunk down to the microscopic level and explore one of your own cells, witnessing the complex and awe-inspiring machinery that powers your very existence. Along the way, you’ll be introduced to the groundbreaking ideas of scientific legends like Charles Darwin, Marie Tharp, Watson & Crick, Barbara McClintock and a whole host of other geniuses from both the past and the present.

A truly comprehensive and deeply accessible guide to the living world, This Is Life will ensure that you’ll never look at living things the same way again.

Genres: Science, Nonfiction

Audible Audio

First published June 25, 2026

About the author

Christophe Galfard is a French physicist and author with a PhD. in theoretical physics from Cambridge University. He is co-author with Stephen Hawking and his daughter on their first YA book, George's Secret Key to the Universe. In the past few years, he has given talks, and written a live show, about our universe attended by more than 130,000 people, of all ages and educational backgrounds.

Reviews

[L. Garrison]

This is Life was less a book and more a journey through the very history of our planet, starting from its very humble origins and ending on the continuing efforts to uncover proof of life beyond our solar system. I was honestly so impressed by the book’s scope; you’d expect a tome attempting to nail down what life is, where it came from, and how it works to be chaotic, unfocused, and just too broad, but the author accomplished the impossible and managed to condense the broad strokes into a handful of hyper-focused chapters.

I especially loved parts 2 and 3, which provided a succinct summary covering everything from Earth’s formation more than 4 billion years ago, to the End Cretaceous Mass Extinction Event of 66 million years ago. The narrative’s use of second person to place the reader directly in the toxic atmosphere of our young planet and then have us endure the immediate aftermath of the dinosaur-killing asteroid was an inspired choice, as it serves to remind us that, as alien as it might have seemed in the earlier eons of its storied history, Earth has been and always will be our planet.

The book also covers quite intense and scientific topics, especially in part 4, which consists of an internal exploration of the cell, and how being composed of cells can be considered a criteria for what can be considered life. However, it is perfectly accessible and breaks down academic topics in ways that are easy for the average non-scientific reader to understand. I also found myself googling a fair few terms, historical people, and concepts because the book stoked my interest into learning more.

This book can also be appreciated for shining a light on scientists who have contributed greatly to the furthering of our collective understanding, some of whom were never justly rewarded for their work. One notable example was Marie Tharp, the geologist who discovered the Mid-Atlantic Rift, an underwater rift that allowed for plate tectonics and continental drift to be widely accepted as fact. Tharp wasn’t originally credited for her work, the acclaim instead going to her male colleague, who didn’t initially accept her discoveries.

This is Life never claims to have all the answers, though it tries its hardest to present everything we currently know in a cohesive and detailed manner. We can quite reliably define what life is, from a human perspective, but we may never know where it actually came from. Our breakthroughs provide ideas for what the very first living organism might have been, but we’ll probably never know for sure. We can guess at the number of planets in the universe that may contain life, but we don’t yet have the technology to ascertain. In this way, this book is hopefully but realistic, and makes it clear there could be further breakthroughs that might one day answer our most burning question: where did life come from?

Overall, I loved this book. It succeeded in making me appreciate the sheer breadth of our planet’s history and understand how small a part of it humans actually have. It was humbling, but in the best way.

[Brian Clegg]

There have been some excellent books on the origins of life, notably Philip Ball's How Life Works and Henry Gee's A Very Short History of Life on Earth, taking distinctive approaches. The field might feel overcrowded - except Christophe Galfard managed to come along with a whole new, highly entertaining take on the project with a physicist's-eye-view.

We begin with evolution. An excellent example of Galfard's sideways take on the topic is the short chapter entitled 'Why alien fish don't fly'. This starts with the reader picturing themselves lying by a river in a forest clearing. A fish jumps out of the river... but doesn't swim towards the clouds, it drops back in. We then pivot to Aristotle dividing the universe into the bit with the Earth and the bit outside the Moon's orbit - and giving us the concept of natural laws (including that a jumping fish will drop back). Then Newton breaks Aristotle's barrier between Earthly things and the heavens, bringing everywhere into the aegis of all natural laws (including those alien fish). Finally, the section transitions into evolution by natural selection. It's mesmerising.

That's just one, four-page chapter of nine in the evolution section alone, each as scattergun and beguiling. We then get on to sections on extinction, the history of Earth, the structure of biological entities, domains of life and ideas on origins of life. All have the same mix of immersing the reader as a character and short chapters with distinct jumps of context. I can honestly say this is one of the most marmite-like (some will love it, some will hate it) books I've read.

I do have a couple of personal issues that admittedly won't be a problem for many readers. It's too long for me - I've never yet read a circa 500 page book that couldn't be usefully edited down a bit. And I sometimes found Galfard boundless enthusiastic mateyness, abruptness and rapid changes of context a little hard going. Quite often, for example, we get a sequence of ultra-short paragraphs, such as:

No nucleus.

Nothing.

Just a membrane with molecules inside.

Hundreds of thousands of molecules busy keeping that strange, simple cell alive.

This approach is central to the nature of the book, but I still have a bit too much British reserve not to find it occasionally grating.

Even so, I can’t remember when I last enjoyed a biology book so much as a pure reading experience. Galfard brings to life his exploration of where we come from a species with remarkable storytelling.

[Jessica]

Thank you University of Chicago Press for providing an ARC for review consideration via NetGalley! All opinions are my own.

This Is Life was my first introduction to theoretical physicist Christophe Galfard - a former graduate student of Stephen Hawking - but it won't be my last! It took Galfard eight years to write this volume, which is not surprising since it is packed with information presented in such a thoughtful way.

Parts one through three cover evolution, earth's history, and various mass extinction events. The last two parts discuss our likely origin story and the potential for extraterrestrial life. These areas are my jam so I could have had the entire book revolve around just these topics and been completely fulfilled. Yet the book is about life so, while not my favorite topics to learn about, the center part importantly dives into DNA, RNA, nucleic acids, and the like.

Galfard illustrates the extreme fragility and precise conditions required for life with jaw-dropping historical facts. For example, the fifth mass extinction (which wiped out the dinosaurs) was actually the weakest one. By contrast, a separate volcanic event lasted tens of thousands of years, burying an area six times the size of the UK under 2.5 kilometers of lava. During the Cryogenian ice age, the planet froze from pole to pole into a giant ball of ice for 100 million years. Meanwhile, tectonic plates shifted continents at a slow 3mm a year—a reminder that our planet is never stagnant. Earth's tumultuous past is filled with extinct species, extreme climates, glaciations, and meteor impacts. It proves that nothing looks the same as it did then, nor will the future look like today. Evolution even gives species latent abilities they might never use unless a specific need arises. Remarkably, we still share common ancestors and DNA with all species—even fruit flies and bananas—and with organisms living by deep undersea hydrothermal vents, the future of life remains excitingly unpredictable.

Galfard’s approachable style mirrors Carl Sagan; reading it feels like chatting with the author or attending an intimate lecture. He seamlessly layers facts with memorable stories to prevent information overload. Best of all, he injects a soothing, almost ASMR-like tone, inviting readers to pause, breathe, and imagine themselves inside deep space, on Earth, or within the human body.

Read more of my book reviews here...
https://fortandfield.blogspot.com/202...

[Mutalib Abubakar]

This Is Life is a fascinating book that explores the connection between the universe and our own existence. Christophe Galfard takes readers on a journey through space, time, and the science behind how life came to be. He explains complex ideas about the cosmos in a way that feels engaging and easy to follow.

What I enjoyed most about the book is how it makes you think about our place in the universe. It combines science with big questions about life, existence, and the mysteries we are still trying to understand. Galfard’s storytelling makes the wonders of space feel closer and more personal. It’s a great read for anyone curious about science, the universe, and the story of how we became part of it.

[Peter Jones]

Fascinating. A very good way of making science understandable to less scientific types like me.

[Jenna Collins]

A satisfying read overall.