This is an inside look of the modern special operations frogman, who make up some of the most elite warriors on planet. A frogman is someone who is trained in the employment and operation of Self-Contained Underwater Breathing Apparatuses (SCUBA) specially rebreathes; closed circuit oxygen and/or mixed-gas rigs that recycle the diver's exhaled carbon dioxide, leaving no tell-tail bubbles associated with open circuit air rigs used by recreational divers. Such personnel are also known by the more formal names of combat diver, or combatant diver, or combat swimmer.
Of interest, "Combat swimming" is often used to mean "combat diving", but according to some strictly speaking means surface swimming without a breathing apparatus for coastal or ship infiltration. Such actions are a historical form of "frogman" activity and an important feature of naval special operations. In the United States Special Operations Forces, divers are called "combat divers". This term is used to refer to the Navy SEALs, elements of Marine Recon, Army Ranger, Army Special Forces, and Air Force Pararescue.
This book covers many naval Special Forces of various countries from around the world, coving history, employment, organization, operations, weapons and equipment in excellent detail and generally underwater warfare as whole. The book discusses the working of closed circuit rigs, mini-subs and other specialty equipment like underwater guns. As well as details are provided on various operations and mission types performed by frogmen like; sabotage, beach surveys, direct action (limpet mine attacks), infiltration, and other clandestine/covert actions.
Overall this is a dated book but still remain one of my favorite books on modern naval special forces. I highly recommend this book and it you like this one also look into the authors other book, "Naval Elite Units" covering the same topic, this book is an Osprey Publishing "like" formatted book, very thin but highly illustrated. Another favorite book is "The Illustrated Guide to the World's Top Naval Special Forces Units" by katz, that has a little more current information but is predominately an illustrated book.