Leni Riefenstahl was a great, if politically controversial, movie director, but only later in her life she picked up photography in a serious way. Her books on African tribes are justly famous.
Then, at age 70 (yes, seventy) she decided to pick up SCUBA diving so as to be able to photographs the underwater wonders she had seen in Kenya. She lied about her age, she looked much younger so she could easily pass for a 50 yo when she was 70, and signed up for a course. In a few years she had produced what at the time must have been one of the best underwater photography books around. The book also has a few pages of introduction by the author on how and why she got in this new challenge so late in her life. This is her amazing foray into underwater photography!
Today, of course, technology has improved a lot and some of these pictures do not look so impressive. Also, some may have been blown up too much and show much grain and poor resolution. But this book must be seen in the context of what underwater photography was 40 years ago, in the early seventies. Today, it is still a must for collectors of underwater photography history books. Translations into German, Italian and perhaps other languages are available in the second hand market.