Richards, Denis: The Fight At Odds.v1. 6 Nov 2012
This book is the first volume of a three part series: The Royal Air Force 1939-1945. It details the role of the British Royal Air Force from the start of World War II from its threadbare beginnings through the triumph over the Axis.
It is an official history, but is from the Air Force point of view. As such it is a valuable supplement to more complete histories of the period.