This is a very detailed study of midget submarines covering Italian, British, German and Japanese accomplishments. The Italians were leaders in this area in WW II with very good equipment and very brave and well trained crew. The Germans on the other hand, started in midget subs late and never really developed good craft. Their crews were unqualified and poorly trained. The author gives detailed technical information about each type of craft plus exciting episodes of the use of these craft in attacks on their enemies.
An interesting side light of this book is the opening chapter that covers the develpoment of the first recorded midget sub the Turtle, used against the British ship HMS Eagle in New York harbour during the War of Independence. ( )

A straightforward account of the use of midget submarines in war, focussing mainly on World War II, but also including a short discussion of early experiments in the American war of independence and World War I, and a more speculative chapter on the naval use of midget submarines since 1945.

Much of the story has been told before elsewhere, of course, but the strength of this book is in putting detailed accounts of the Italian, Japanese, British and German work side-by-side, augmented by a certain amount of original research and discussions with veterans from all four countries. Kemp gives a very clear account of the practical difficulties and dangers faced by the crews of midget submarines, the limitations of the available technology, and the reasons for the successes and failures of the different projects: the Italians had superbly trained and motivated men who succeeded with rather rudimentary equipment and made opportunities to use it effectively; the Japanese had excellent equipment but it was designed for the wrong purpose; the British profited from the Italian experience but were only occasionally in the right place at the right time; the Germans had the right idea, but started at a stage in the war where thay simply didn't have time to overcome technical problems and train personnel.
Perhaps one of the most telling comments in the book is the suggestion in the last chapter that the Royal Navy scrapped its midget sub operations in the 1950s mainly because the training programme was too dangerous to be justifiable in peacetime.