In the spring of 1940, then-unknown writer Albert Camus and budding biologist Jaques Monod quietly joined the French Resistance as they watched their beloved Paris fall to the Nazis. Decades later, after stumbling across a few lines in a biography, Sean B. Carroll, an evolutionary biologist, author, and alumnus of Washington University in St. Louis, set out to prove that these two great minds were also friends. Rooting through French archives and talking to people at the heart of the French Resistance, Dr. Carroll uncovered documents no one expected to find and illustrates the exciting turns historical research can take.