The previously classified story of the eccentric researchers who invented cutting-edge underwater science to lead the Allies to D-Day victory

In August 1942, more than 7,000 Allied troops rushed the beaches of Normandy, France, in an all but-forgotten landing. Only a small fraction survived unscathed. It was two summers before D-Day, and the Allies realized that they were in dire need of underwater intelligence if they wanted to stand a chance of launching another beach invasion and of winning the war.

Led by the controversial biologists J. B. S. Haldane and Dr. Helen Spurway, an ingenious team of ragtag scientists worked out of homemade labs during the London Blitz. Beneath a rain of bombs, they pioneered thrilling advances in underwater reconnaissance through tests done on themselves in painful and potentially fatal experiments. Their discoveries led to the safe use of miniature submarines and breathing apparatuses, which ultimately let the Allies take the beaches of Normandy.

Blast injury specialist Dr. Rachel Lance unpacks the harrowing narratives of these experiments while bringing to life the men and women whose brilliance and self-sacrifice shaped the outcome of the war, including their personal relationships with one another and the ways they faced skepticism and danger in their quest to enable Allied troops to breathe underwater.

The riveting science leading up to D-Day has been classified for generations, but Chamber Divers finally brings these scientists’ stories—and their heroism—to light.

"In Chamber Divers, we are told that by the outset of World War II, scientists still knew very little about decompression sickness... Enter into this netherworld a small group of intrepid scientists... Their experiments were harrowing." —Wall Street Journal

“A riveting account of the daredevil Allied researchers who made advances in underwater warfare possible during WWII…Propulsively narrated and full of moments of astonishing sacrifice, this brings a remarkable history to light.” —Publishers Weekly (STARRED REVIEW)

“In this bracing history of an obscure but significant aspect of the D-Day landing, Lance (In the Waves, 2020) combines a staggering amount of research with an array of compelling personalities to tell an unforgettable story.” —Booklist (STARRED REVIEW)

“A fascinating, hair-raising account of groundbreaking research.” —Kirkus

"Lance’s singular strength is her lucid explanations of complex science, making it accessible to untrained readers.” —BookPage

“With skill and heart, Rachel Lance tells the story of a group of unlikely heroes, who sacrificed their own bodies to advance a hidden world of warfare. Exploring the unseen depths of WWII’s most dangerous operations, Lance reveals the secret wartime science that remains essential to protecting our freedoms.” —Nathalia Holt, New York Times bestselling author of Rise of the Rocket Girls and Wise Gals

"Meticulously researched, the unbelievable yet true story of the eccentric, maverick submarine scientists whose courage and expertise ensured the success of D-Day. Inspirational reading."
—Dr Helen Fry, author of MI9

“Rachel Lance has produced a gripping, beautifully researched narrative that plunges readers deep into the drama of one of the most important military operations in history. WWII buffs and those looking for a genuine page turner will be delighted.”
—Alex Kershaw, New York Times bestselling author of Against All Odds

“An illuminating account of the women and men whose dogged efforts and sacrifice helped to enable and protect the most critical, but also most fragile weapon in war – the human body. Chamber Divers sheds new light on an little-known aspect of some of history’s most famous operations. Entertaining and informative – a great read.”
—General Stanley McChrystal, USA, New York Times bestselling author of My Share of the Task and Team of Teams