William Martin is the leader of the Aquanauts.
This group of highly trained operatives is part of the elite Secret Underwater Service. To provide adequate protection to the nation from enemies who would either strike from the sea or attack naval underwater missions, the U.S. Navy established this top secret organization. The mission of the SUS was twofold: train personnel to be able to handle extremely difficult underwater missions and to actually carry out those tasks when the President so orders.
The men who volunteer for such a position were dubbed the Aquanauts. Classified as Minnows at first, they were able to assume the much coveted name of Shark when they had proven their abilities. The best man of the group was alone given the title of Tiger Shark and was empowered to do whatever was necessary on a mission - even kill.
The first man to be so named died in action. His replacement was William (Bill) Martin, a lieutenant in the Navy and a decorated war hero with a Navy Cross with oak leaf cluster. Standing 6'2 and weighing 215 lbs, this black-haired, blue-eyed Annapolis graduate was 30 years old and in perfect physical condition.
He was also exactly what this clandestine organization demanded - a rugged, fearless man who put the interests of the country before those of his own.
A common belief about this series seemed to be that it was for young adults. The Sea Hunt style covers, adolescent titles (Operation Sea Monster and Operation Mermaid), and a hero with the name Tiger Shark, all contributed to that image.
Reading them, however, will change that attitude. While they are somewhat juvenile, they are hardly meant for a juvenile audience. Fairly good love scenes and vicious knife fights abound throughout the pages. One book even starts with a man's plan to change his sex!