Medusa by Clive Cussler - A Kurt Austin Adventure

"In the Micronesian Islands, a top-secret, U.S. government-sponsored undersea lab conducting vital biomedical research on the rare blue Medusa jellyfish disappears. At the same time, off Bermuda, a bathysphere is attacked by an underwater vehicle. Only Kurt Austin can save its passengers from a watery grave. Austin, suspecting a connection between the two mysterious events, puts the NUMA team on the case..." This book has been read many times and shows signs of wear-and-tear.