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 served in the 5th Special Forces Group in Vietnam in 1969-70 and subsequently in airborne infantry, long-range patrol and intelligence assignments before retiring after 26 years. He was a Special Operations Forces scenario writer at the Joint Readiness Training Center for 12 years and is now a freelance writer, living in Texas.