British submarine design across two world wars

Norman Friedman's British Submarines of Two World Wars combines plans, photographs, references, and detailed design history. Early boats, Thunderbolt's gun, and the R class show how far these craft could differ from later streamlined submarines. The earliest types were submersible torpedo boats, far removed from submarines in the modern sense. The T class was designed for the Far East and the S class for the Mediterranean and North Sea, yet wartime needs often sent boats to other theatres. The combination of plans and operational context makes the volume useful for following technical development and wartime adaptation together.