While much has been written about the German U-boats of World War II, virtually nothing has been forthcoming on the Japanese 'I-boats'. The I-400 'super submarine' was one of the most monstrous creations to emerge from the Second World War and in its time it was the largest submarine ever built. It was considered to have been one of Japan's most secret weapons - indeed the Allies remained unaware of its existence until it surrendered in late August 1945. At more than 400 ft long,weighing 5,700 tons, carrying a crew of 200 and possessing a range of over 50,000 miles, the I-400 carried three Seiran attack floatplanes in a hangar built on to its deck ahead of the massive conning tower. The Imperial Japanese Navy tasked the I-400 with a secret mission to attack American cities and to destroy the Panama Canal. This book is the result of many years of meticulous research.The authors have traced and interviewed three of the original six pilots slated to fly the Seirans on their hazardous missions. They have revealed - for the first time - the story their aircraft being painted in fake US markings for their final mission. The story is also told using first-hand accounts from former officers and crew of the I-400 and those American naval personnel who 'crewed' the vessel on its final voyage. The book contains hundreds of astonishing photographs, many previously unpublished, showing the I-400 from both outside and inside as well as its hangars and aircraft.