One of the more insightful books I read was The Authoritarians by Robert Altemeyer. I first found out about his incredible studies on authoritarian personalities reading John Dean's Conservatives without Conscience. Then in 2007, Dr. Altemeyer provided a very readable and accessible online book which synopsized his studies from his decades of research.
The good news is that an audio version of The Authoritarians, read by Dr. Altemeyer is now available through Cherry Hill Publishing. You can get the CD by going to their site and they plan to provide a downloadable version soon.
If you ever wondered why things got so bad so fast under Bush, you owe it to yourself to understand what it is about the authoritarian personality that made it so predictable.