This comprehensive and detailed book starts with the UK's preparation for war in 1939 then discusses how the plans changed as a result of the Dunkirk evacuation and the Battle of Britain. The Battle of Britain is covered in great detail, but there are better accounts. The high point of this book are the chapters on the V weapons. Much of the intelligence and tactics used will be unfamiliar to the reader and shed a different light on the nature of WWII.
The flying in of a DC 3 to a German temporary airfield at night to recover the guidance system of a V2 has to be one of the triumphs of the Polish underground