I had the pleasure of receiving yesterday Don Hahn's new book The Alchemy of Animation: Making an Animated Film in the Modern Age. This book is clearly a very good surprise: it is very readable (Don Hanh's previous book was too), longer and much better illustrated than Hahn's Disney's Animation Magic.
Is this a Disney-historian dream? Frankly it isn't and it isn't meant to be. It is clearly a book aimed at a very general audience. And that goal is reached, with honors. In fact, I believe this book is doing exactly what The Art of Animation by Bob Thomas did in its time: it creates a nice window in the life of current Disney artists and on the world of Disney animation. If I were a kid today, this book would definitely get me excited and make me want to become an animator (if I had any talent that is!) Everything is clearly explained and the book does not talk down to its audience in any way.
Conclusion: Not a revolution in terms of Disney history, but wonderful book for your kids and great book for Disney enthusiasts thanks to the artwork selection.