I believe this is the first book ever published on underwater photography.
La photographie sous-marine et les progrès de la photographie
by Boutan, Louis, 1859-, Originally published in1900
I have a copy of the magazine article publish shortly before the book with some photos and text which I have seen several times for sale for ~$20 USD. I have only found two copies of the book up for sale and both were a bit out of my budget. The first was ~$500 USD. The second copy is curently on ebay with a price of US $3,456.49
http://www.ebay.com/itm/Photographie-so ... SwIgNXmJoV
The book is now in public domain and can be purchased as a reproduction:
https://www.amazon.fr/photographie-sous ... 2012724523
The following online archive has legal downloads available for free in several formats:
https://archive.org/details/laphotographieso00bout
If you view the online book in thumb view you can advance to the photos and diagrams and avoid the french language. The pages are high resolution so once you are on a page you like you can enlarge it for greater detail.