Vacation Reading and reading to learn/improve are totally separate IMO. One is mindless entertainment, the other is intensive, time consuming, and needs application to be worth it.

If the latter:
The Henry Watts book is good if you are *just* starting out, but honestly an Evolution School day will teach you more.

Drive to Win, Tune to Win, basically the entire "---- To win" series by Carrol Smith is good. He's pretty arrogant about alot of things, but you have to be to win.

Also "Going Faster: Mastering the Art of Race" driving is an ok book.

IMO Seat time absolutely, irrevocably owns on reading a book. The $400 a pair of Evo schools, or a double weekend at the track costs, is far greater than that cost in books.