Middlebrook wrote his first book The First Day on the Somme (1971) following a visit to the First World War battlefields of France and Belgium in 1967. This is a detailed study of the single worst day for the British Army. Middlebrook gave the same single-day treatment to 21 March 1918, the opening of the German Spring Offensive, in The Kaiser's Battle. Middlebrook's Second World War books concentrate on the air war. A number of them again deal with a single day of action (The Nuremberg Raid, The Schweinfurt–Regensburg Mission and The Peenemünde Raid) while others cover longer air battles (The Battle of Hamburg and The Berlin Raids). Middlebrook has also written two books on the Falklands War, one from the British and Falkland Islanders' perspective and one from the Argentinian perspective.