Much more comprehensive than the camera manual is Graphic Graflex Photography by Willard Morgan and Henry Lester. The 8th edition of 1947 covers up through side rangefinder Crowns. I don't know which edition covers the top rangefinder models. This book is usually available from online booksellers such as http://www.abebooks.com/
Good point, Jim. I have a copy of that book and it covers just about everything they made. They go for cheap if I remember correctly. If you can't find it at Abebooks, try Powells or Alibris (both .com).