I've read Cassingham's The Dvorak Keyboard and most of Dvorak's Typewriting Behavior. They're both very good if you're really interested in typing, but I especially appreciate The Dvorak Keyboard for its focused Dvorak information.
The Dvorak Keyboard is whole-hog Dvorak. It has a lot of history about how the QWERTY and Dvorak layouts came to pass, plus a lot of information from studies Dr. Dvorak did for the Navy several years after he published his Typewriting Behavior (discussed below). Conspiracy fans take note: the Navy was all set to convert to Dvorak, but funding was mysteriously withheld and the whole project classified at the last minute!
Cassingham also lays out an approach to retraining for Dvorak. The list of sources printed in Cassingham's book is well out of date, but my copy came with a separate source list that was more current.
You might think it odd, but Dvorak's book hardly mentions the Dvorak ("simplified") keyboard. Dvorak and his co-authors go into depth about the psychology and physiology of typing; especially learning how to type and correcting "difficult typing behavior." Although there is a good bit of hard data about finger loading, digraphs, and other things that make the Dvorak keyboard really cool, it sort of gets lost in the other 400-odd pages.
Most of Dvorak's book applies to typing in general, and I recommend it if you really want to wade into typewriting studies. Some of the 1930's psychospeak sounds odd, but my Psych-major wife says the old stuff can still be pretty current. I guess a salivating dog is a salivating dog, for all that. (Oh yes; dogs, rats, and chimpanzees all have a place in this book. It dips into some bare-metal behavior study.)
BTW, if anybody has wondered about the odd logo on this page and on most of my Netscoop backgrounds, it was inspired by the title-page logotype in Typewriting Behavior.
Randy is the only source for Typewriting Behavior, and it's been out of print for 60 years. If he runs out before you get yours, well... try another library.
Disclaimer: I have no financial interest in Freelance Communications. So there.
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