The story of the Battle of the Atlantic is well known. It was fought over many thousands of square miles of ocean and lasted until the German surrender in May 1945. The inability of the Germans to win the Battle of the Atlantic greatly reduced their their hopes of winning the war. Strangely there was no Battle of the Pacific as such. The battle of attrition between the American and Japanese fleets never took place and thousands of American ships crossed the Pacific, in support of their army's island-hopping campaign, almost unscathed by attack from Japanese submarines. The Indian Ocean provided an altogether different scenario as it was the one area of the world where, uniquely, the submarines of seven nations — Great Britain, the Netherlands, USA, France, Italy, Germany and Japan - all operated and fought during the war. Michael Wilson, an ex-submarine officer, presents an authoritative account of the Second World War operations usinng archive material from all the countries that were involved. It is not intended to be a detailed comprehensive chronology of who sunk what and when, but rather a look at the overall picture of how the submarines  were deployed and the level of success they achieved.