I have lost the cover of this book, so these are the first inside pages. The book charts the story of the Bathysphere Trieste which decended seven miles into the Chellenger Deep off Guam in 1960. As far as I know this has never been replicated
Later Picard used another sub in 1969 to chart the Gulf Stream. I actually met the man in the West Indies when I was on H.M.S. Rhyll. This is a facinating book of the beginning of ‘inner space’ exploration.
There is no ISBN.