After reading a well-worn copy of Thomas Gallagher’s book The X-Craft Raid, I have been fascinated by mini-subs and the missions they completed or attempted during the Second World War. Three X-craft were to sink the Tirpitz at her berth in Norway, and the mission was moderately successful in that they were able to damage the German battleship in such a way she was out of action until spring of 1944. I learned that many countries produced midget submarines during the war, and Mr. Bauernfeind’s book, Midget Submarines 1939–45 covers these craft comprehensively. Molch, Biber, Seehund (Germany), Kaiten, Ha Series, Kairyu (Japan), Type Ca, Type CC (Italy), X-Craft, XE-Craft, and Welman (United Kingdom); these and more are midget submarines examined in this new Casemate publication.