During the immediate period before World War Two, the RAF modified its command structure to rationalize for rapid expansion. Bomber Command was divided into six operational groups, each flying the same type of aircraft, including Wellingtons, Sterlings, and Lancasters. Chris Ward presents us here with the history of 4 Group Bomber Command, having previously acquainted us with the histories of 3, 5, and 6 Group Bomber Commands in three highly acclaimed volumes, published by Pen and Sword. He continues with characteristic ease, quality of research, and narrative pace, to present us with an operational record of the group's activities during a particularly dramatic period of aviation history. The book contains individual squadron statistics, their commanding officers, stations and aircraft losses. It provides a detailed reference for one of the RAF's most important operational groups.