I was searching around for information on different cams when I came across Wild Country’s Cam Book.  This is an online “book” you can download and contains some of the history of the development of the Caming unit by Ray Jardine and the start of its production by Mark Vallance.  Also it goes into a pretty in depth look at how cams work and more specifically how Wild Country caming units work. It’s a little heavy but for any gear junkie out there it is a worthwhile browse. Also worth looking through is the article
The Nuts’ Story: Clockwork Friends