From the warmer climate of the Mediterranean to the frozen wastes of Norway's Arctic islands, the Combined Operations organization was a persistent thorn in the side of Hitler's Third Reich. From mounting attacks against enemy-held coastlines with small teams of less than a dozen men, through to huge expeditions involving thousands of troops and other personnel, the headquarters of Combined Operations oversaw a wide variety of amphibious operations, all undertaken with the sole aim of tying down the Führer's forces.

The raids, both big and small, were mounted as frequently as possible against anywhere boats could reach, keeping the Axis forces constantly on guard. The effects of the early Combined Operations far outweighed the resources committed to the raids, with an extra 30,000 German troops being sent to garrison Norway following the Commando raids, the largest of which included only around 500 men.

The Combined Operations organization grew as the war progressed, and it was instrumental in the planning and training of troops and the provision of landing craft for the amphibious assaults which saw the capture of French North Africa, Operation Torch, and the invasion of Sicily, Operation Husky. Its culminating glory came in the summer of 1944, when the largest amphibious operation in history saw a quarter of a million men shipped across the English Channel to the beaches of Normandy on D-Day and its aftermath.

Combined Operations is an official history that explores the full story of how the body was set up, its structure, and how it put together the hugely complex tri-service operations. Also detailed is how its headquarters staff operated, and how the planning section functioned - in 1942, for example, the planners envisaged one raid every month, which culminated in the disastrous Dieppe raid in August of that year.

The Combined Operations organization was also instrumental in the development and provision of specialist landing craft and ships, and of the clearing of beach obstacles and mines - all of which is explored in detail.

As might be expected, a large proportion of the book is dedicated to the various and fascinating projects in preparation for Operation Overlord which saw the culmination of everything that had been learned, in the successes and failures, throughout four years of amphibious warfare.