Preparing for Victory explains how and why Commandant Thomas Holcomb successfully supervised the dramatic expansion of the Marine Corps from 18,000 officers and men in 1936 to 385,000 in 1943. Not only did Holcomb leave the Corps much larger, but he also helped establish it as the United States’ premier amphibious assault force and a major contributor to victory over Japan. Despite Holcomb’s successes, he has been ignored or given short shrift in most histories of the Marine Corps. No book-length study of his commandancy exists until now. Drawing on a wide range of printed and archival sources, my book contends that Holcomb expertly guided the Corps’ preparations for war during the last years of the Great Depression and then provided his “Leathernecks” with astute direction during the first harrowing twenty-five months of World War II. When measured with principles of organization theory and leadership studies, Holcomb’s abilities and achievements match those of such outstanding American military managers as Dwight D. Eisenhower, Chester W. Nimitz, and George C. Marshall. Like these unassuming yet efficient officers, Holcomb shied away from the limelight and therefore never garnered the attention that “Chesty” Puller or “Howlin’ Mad” Smith have. This book fills a void and tells the story of one of the key leaders in World War II. More than any other marine, Holcomb molded his Corps into the modern force-in-readiness that would eventually help fight the Cold War and the Global War on Terror.