I have to say that I think this book has the wrong title. This is the very interesting history of HMS Petard, a ship of the royal navy. Background is given on the state of war into which the vessel was actioned, its a relatively detailed background considering the shortness of the book. Petard's uncredited capturing of a vital enigma machine is detailed as is her further career in other theatres throughout the remaining war. This is a well written account of the ship's actions, the bravery of her crew and the historic importance of her role. I found it fascinating.