To his admirers, Luis W. Alvarez was the most accomplished, inventive, and versatile experimental physicist of his generation. During World War II, he achieved major breakthroughs in radar, played a key role in the Manhattan Project, and served as the lead scientific observer at the bombing of Hiroshima. In the decades that followed, he revolutionized particle physics with the hydrogen bubble chamber, developed an innovative X-ray method to search for hidden chambers in the Pyramid of Chephren, and shot melons at a rifle range to test his controversial theory about the Kennedy assassination. At the very end of his life, he collaborated with his son to demonstrate that an asteroid impact was responsible for the extinction of the dinosaurs, igniting a furious debate that raged for years after his death. Alvarez was also a combative and relentlessly ambitious figure who testified as a government witness at the security hearing that destroyed the public career of his friend and colleague J. Robert Oppenheimer. In the first comprehensive biography of Alvarez, Alec Nevala-Lee vividly recounts one of the most compelling untold stories in modern science, a narrative overflowing with ideas, lessons, and anecdotes that will fascinate anyone with an interest in how genius and creativity collide with the problems of an increasingly challenging world.