History was made when the bathyscaph Trieste carried Jacques Piccard and Lieutenant Don Walsh of the U.S. Navy to the deepest known point of the world's oceans, the bottom of the Challenger Deep in the Pacific off Guam. This book is the complete story of the invention and development of the bathyscaph. It covers the Trieste's European sponsored dives off Italy (1953-56), the Mediterranean dives sponsored by the U.S. Office of Naval Research in 1957 leading to the purchase of the Trieste by the U.S. Navy, subsequent dives off San Diego, and finally an engross- ing description of the ultra-deep dives - seven miles down - of Project Nekton. Illustrated with 32 pages of photographs, the book is a complete and fascinating account of one of the great scientific adven- tures of our ships of tomorrow, of which the Trieste is a blind and cumbersome prototype. It discusses the future of oceanography and what is yet to be learned from the depths of the sea. Mineral resources lie untouched and waiting, and the authors anticipati:. that, for both com- mercial and military reasons, there will SOOt:l be a vast international invasion of the underwater world.