When I was pregnant, I read all the books I could find so that I was as prepared as I could be for the marathon called childbirth. These books come highly recommended for all Mommies-to-Be!
The Birth Partner
by Penny Simkin
If you don't take any childbirth prep course, this is an absolute must-read. And even if you do take a course, it's great to have everything in one place so you can refer to the book as you need it.
Husband-Coached Childbirth
by Robert A. Bradley
The classic book by the inventor of the Bradley Method. The writing is a bit old-fashioned, but it's a must read for anyone who would like to attempt giving birth the "natural" way. This book is required reading if you take a Bradley Method course.
Natural Childbirth the Bradley Way
by Susan McCutcheon
Contains tons of practical exercises, positions that you can practice with your partner, and dieting advise. This book is another required reading if you take a Bradley Method course.