Armed to the teeth with heavy weapons, the Royal Navy's D class MGBs and MTBs played havoc with enemy convoys during World War II, engaging and sinking dozens of vessels. This account of the Dog Boats in action draws upon offical records and eye-witness testimony to examine their contribution to the defence of the Normandy landings assault areas, and their clandestine, special duty missions to pick up agents and RAF pilots passed back along the escape routes of the French Resistance.