One of my absolutely favorite books is Shadow Divers
Amazing story about the obsession they had with solving the riddle of an unknown. U-Boat off the cost of New Jersey, and it covers the days when there were still people doing extreme diving with air, and not gas mixtures.
The Rouses’ lived not far from me & dove out of the same dive shop that I use in Horsham, PA. I did not know them, but others that I run into did.
A better book on the incident is entitled “The Last Dive”.