The outbreak of World War II set in motion a massive expansion of the United States Marine Corps, leading to a 24-fold increase in size by August 1945. This book is the first of several volumes to examine the Corps's meteoric wartime expansion and the evolution of its units. It covers the immediate pre-war period, the rush to deploy defense forces in the war's early months, and the Marines' first combat operations on Guadalcanal, New Georgia, and Bougainville. It focuses on the 1st, 2d, and 3d Marine Divisions (MarDivs) and the provisional 1st, 2d, and 3d Marine Brigades (MarBdes).

Gordon L Rottman entered the US Army in 1967, volunteered for Special Forces and completed training as a weapons specialist. He was assigned to the 7th Special Forces Group until reassigned to the 5th Special Forces Group in Vietnam in 1969-70. Gordon worked as a civilian contract Special Operations Forces Intelligence Specialist at the Army's Joint Readiness Center, Ft Polk, until 2002. A highly respected and established author, he now devotes himself to full-time writing and research.