Michael Welham is the author of Combat Frogmen; Naval Elite Units; Exploring the Deep; Frogman Spy; and KampfSchwimmer (German edition of Combat Frogmen). He has been involved with diving, both military and civilian, for some 40 years, and was a Royal Marines Commando, with skills in diving, canoeing, and parachuting; a member of 21 SAS Rgt (R); and 95 Commando Naval Gunfire Support RA (R). From commercial deep diving around the world he spent fifteen years as a UK Government diving officer.