Book excerpt: Enemy Sighted is the story of the world’s first integrated air defense system and how the coalition of Hurricanes and Spitfires, Fighter Command’s Operations Rooms and Sector Stations, Radar Stations, Observer Corps posts, anti-aircraft gun and searchlight batteries, and balloon barrages, stood resolutely in the way of Operation Seelöwe, Hitler’s plan for invading Britain in the Summer of 1940. Dilip Amin provides a fascinating insight into their development and eventual operationalization. The system provided a recognized air picture, giving everyone the same information at the same time, much like computers linked through the internet do today, except, in 1939 there was no computer and there was no internet! Fundamental to its telling is the 11 Group Operations Room, today referred to as the Battle of Britain Bunker, and the people who worked there, deep below RAF Uxbridge. It was after visiting the Bunker that Churchill first uttered the immortal words, ‘Never in the field of human conflict was so much owed by so many to so few’. Hidden underground, with its large map table and squadron display boards, and balloon and weather states, it is preserved as it was on 15 September 1940, the date celebrated as Battle of Britain Day. Dilip Amin describes how the Bunker operated, transporting the reader back to the time of the Battle of France and the final evacuation from Dunkirk. He guides the reader through the Battle of Britain, examining in detail, the events of 15 September, as seen by those in the Bunker and the combat reports of those flying the Hurricanes and Spitfires on that tumultuous day. Finally, the book provides an insight into how the Bunker operated to protect Britain during the Blitz; support the exploratory raid on Dieppe; shield the troops landing in Normandy; and defend against Hitler’s V1 and V2 Vengeance Weapons. Enemy Sighted provides a compelling insight into the remarkable history of a secret Operations Room, that was pivotal within a world leading air defense system, and without which, an Allied victory in the Second World War would have been far from certain.