The thrilling true story of the unlikely American codebreakers, chiefly composed of civilians, Jews, and women, who cracked Japan's impenetrable communications with the Nazis and helped end World War II—from an award-winning historian

In 1937, Japanese engineers invented the Purple Machine, a cypher capable of scrambling a message more than 500 quadrillion ways. It was a near-perfect encryption device, used by Japan to communicate many of the Axis powers’ deepest secrets during World War II. Japanese intelligence believed Purple would remain secure for decades to come.

In 1940, a small, scrappy group of American codebreakers in Washington DC proved them wrong.

Code Name Purple is the story of the team of outsiders that broke Purple. For years, high-level codebreaking had been dominated by military men, but this group was largely recruited as civilians, coming from a myriad of backgrounds, faiths, and life experiences. Working in shabby, poorly insulated rooms, they accomplished one of the greatest codebreaking feats of all time—and in doing so, they helped defeat the Nazi regime that considered so many of them subhuman.

Based on thousands of pages of interviews, personal papers, and recently declassified archival documents, award-winning historian Amy Butler Greenfield brings these outsized characters to life, including William Friedman, the troubled Jewish genius who hand-picked the team, and Genevieve Grotjan, the brilliant young mathematician who would make the most crucial breakthrough.

Amy Butler Greenfield crafts a stunning narrative history, not only of their work, but of their lives—poker games, parties, arguments, anguish, friendships, romances, and their courage in peace and war. Set in an era when no one was sure if humans could keep up with machines, Code Name Purple is a rigorously reported and powerfully told story of frailty, resilience, and what it means to be human.