The Walt Disney Film Archives: The Animated Movies 1921-1968 is a phenomenal undertaking. It's a huge book (624 pages) and some of the best Disney historians have been asked to write chapters for it, including Leonard Maltin, Charles Solomon, J.B. Kaufman, Mindy Johnson and yours truly.
I had the pleasure of writing the chapter about the making of The Reluctant Dragon. This was no easy task, but I believe that you will discover a lot of information by reading the chapter. I stumbled upon quite a few new facts while researching it. And as always I tried to quote from sources that are not easily available.
The other thing that is exciting about the book is that it will contain a huge amount of never-released-before artwork. The only chapter whose pages I have seen to date is the one about The Reluctant Dragon, but from all of the information that I was able to gather from people who worked on the project the visual content of most of the other chapters will be as exciting as the text itself.
Did I already mention that I can't wait!?