As I have stated before, I will update any new information I find on them in books, articles, ect.
Today I have recently updated two of the all-time greats, Clarence Sinclair Bull and Ruth Harriet Louise.
Here are the links:
The new info comes from a wonderful book called "Glamour of the Gods" (showcasing The John Kobal Collection) which discusses a lot of the Hollywood photographers from many different studios including, MGM and Paramount among others. A highly recommended book!
So be sure to check this out. I will continue to update as I can.