Unbreakable: The Spies Who Cracked the Nazis' Secret Code

by Rebecca E F Barone (Author)

Unbreakable: The Spies Who Cracked the Nazis' Secret Code
Reading Level: 6th − 7th Grade

Unbreakable is the edge-of-your seat true story of the codebreakers, spies, and navy men who cracked the Nazis' infamous Enigma encryption machine and turned the tide of World War II--perfect for fans of The Imitation Game.

A thrilling adventure of intrigue and daring worthy of the best James Bond stories. --James Ponti, New York Times best-selling author of City Spies

As the Germans waged a brutal war across Europe, details of every Nazi plan, every attack, every troop movement were sent over radio. But to the Allied troops listening in--and they were always listening--the crucial messages sounded like gibberish. The communications were encoded with a powerful cipher, making all information utterly inaccessible . . . unless you could unlock the key to the secret code behind the German's powerful Enigma machine. Complete with more than sixty historical photos, Unbreakable tells the true story of one of the most dangerous war-time codebreaking efforts ever. While Hitler marched his troops across newly conquered lands and deadly "wolfpacks" of German U-Boats prowled the open seas, a team of codebreakers, spies, and navy men raced against the clock to uncover the secrets that hid German messages in plain sight. Victory--or defeat--in World War II would hinge on their desperate attempts to crack the code.

Unbreakable is a groundbreaking work of narrative nonfiction from Rebecca E. F. Barone, the author of Race to the Bottom of the Earth (recipient of four starred reviews)--perfect for fans of Bomb, The Boys Who Challenged Hitler, and The Nazi Hunters.

Select format:

Kirkus Reviews

Starred Review
A riveting true-life adventure story combining brains, courage, and heart.


Starred Review
Historical photos, first-person quotes, and well-sourced back matter support suspenseful writing. Highly recommended.

School Library Journal

Starred Review

Gr 5-8--Deciphering the infamous German military code--helping to end the Second World War--began with the mistaken delivery of an early Enigma code machine to a Polish customs office in 1929. But the focus here is mostly on the heroic work done in the 1930s and 1940s by Polish, French, and British spies and mathematicians, around the clock and under tremendous, often life-threatening, pressure. Some readers will be familiar with computing pioneer Alan Turing and his significant work on the codebreaking project at England's Bletchley Park. But Barone brings much deserved attention to some fascinating figures not often celebrated in popular histories, from Hans Thilo-Schmidt, a German spy and brother of a prominent military officer who secretly shared intelligence with French counterparts for years; to the Polish electronics expert Antoni Palluth, who worked to reverse-engineer the Enigma machine; and British undergraduate Harry Hinsley, whose behavioral insights and math wizardry helped the team at Bletchley Park find new ways of thinking about the code. A showdown between a Gestapo officer and Palluth's wife, Jadwiga, is particularly harrowing. Historical photos highlight important figures and war machinery throughout the text, though the mostly unbroken layout will appeal more to stronger readers. The volume concludes with an annotated time line, extensive bibliography, and a dozen pages of meticulous source notes. VERDICT Engagingly told as a grim race against time, deeply researched, and with ample space for the play of differing perspectives and outsized personalities, this titles is highly recommended for upper elementary and middle school libraries.--Bob Hassett

Copyright 2022 School Library Journal, LLC Used with permission.

Publishers Weekly

Starred Review

"It was unlike anything codebreakers had seen before.... No one could break the German Enigma." Imparting urgency and drive to a telling that begins well before WWII, Barone (Race to the Bottom of the Earth) writes a thriller-like chronicle of the high-stakes quest to decipher the German Enigma machine. The narrative highlights both the complexity of the machine's encryption and the extensive machinations involved in deciphering it, starting with the machine being inadvertently sent to Polish customs in 1929, an event that offered insight into its make and assembly. Vivid portrayals describe the individuals involved in myriad countries' intelligence efforts, including French Intelligence Bureau agent Rodolphe Lemoine; German civil servant Hans-Thilo Schmidt, who sold information to the French government; and Britain's network at Bletchley Park, which included computing pioneer Alan Turing as well as thousands of members of the Women's Royal Navy Service. It's a breathlessly told account of clandestine operations whose success contributed to the war's end. Maps and b&w photographs throughout offer insight to both the mechanical and the historical. Back matter includes an epilogue, timeline, and extensive bibliography. Ages 10-14. Agent: Michael Bourret, Dystel, Goderich & Bourret. (Oct.)

Copyright 2022 Publishers Weekly, LLC Used with permission.

Review quotes

A thrilling adventure of intrigue and daring worthy of the best James Bond stories and made all the better because it's completely true. A common refrain throughout the story is, 'Never repeat something you want kept secret.' So let me say twice, to ensure that word gets out, 'Read this book. Read this book.' —James Ponti, New York Times best-selling author of City Spies

"A taut, suspenseful story. Here is a war that few people know, a race among brains with freedom at stake, brought vividly to life by." —Phillip Hoose, author of the National Book Award winning and Newbery Honor book Claudette Colvin: Twice Toward Justice

A captivating tale of perseverance and grit, Barone kept me on the edge of my seat, reading well into the night. I could not put it down. —Beth McMullen, author of the Mrs. Smith's Spy School for Girls series and the Lola Benko, Treasure Hunter series

Praise for Race to the Bottom of the Earth:

FOUR starred reviews!

I raced to the end of this book! —Alan Gratz, New York Times-bestselling author of Refugee

A nail-biting tale of adventure, tragedy, and superhuman determination. —Elizabeth Wein, #1 New York Times-bestselling author

A huge treat for adventure story fans—not one, but two incredible races across the fearsome and fascinating Antarctic! —Steve Sheinkin, New York Times-bestselling author

Absorbing, compelling, and truly touching. Kids will love this book! —Deborah Heiligman, YALSA Excellence in Nonfiction Award-winning author

A riveting tribute to epic tests of men against the elements. —Kirkus, starred review

A compelling narrative focused on science and technology, embedded in a cluster of thrilling adventure stories . . . Highly -recommended. —School Library Journal, starred review

Readers will be caught up in the real-time action sequences. —Booklist, starred review

Exemplary. —BCCB, starred review

Rebecca E F Barone
Rebecca E.F. Barone is an engineer and author. She has worked on technical projects as diverse as injury analysis for the NFL and engine calibration for hybrid cars. Realizing her love of books in addition to numbers, she now describes the world with words rather than equations. Her first two books, Race to the Bottom of the Earth: Surviving Antarctica and Unbreakable: The Spies Who Cracked the Nazis' Secret Code, received a combined nine starred reviews and were featured on numerous "Best of" lists. She lives in Ohio with her family.
Lexile Measure
Guided Reading Level
Henry Holt & Company
Publication date
October 20, 2022
BISAC categories
JNF025070 - Juvenile Nonfiction | History | Europe
JNF025130 - Juvenile Nonfiction | History | Military & Wars
JNF068000 - Juvenile Nonfiction | Spies & Spying
Library of Congress categories
Great Britain
World War, 1939-1945
Secret service
Enigma cipher system

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