Most CNM schools use Varney's Midwifery for a text. I wouldn't buy it for a good read, it's on the dry side.
http://www.amazon.com/Varneys-Midwif...9853906&sr=8-1
Two books I think do very well at showing what real life is like for a CNM are:
Giving Birth by Catherine Taylor -
http://www.amazon.com/Giving-Birth-J...9853957&sr=1-1
Baby Catcher by Peggy Vincent -
http://www.amazon.com/Baby-Catcher-C...9854038&sr=1-1
Two books that will probably depress you and convince you not to become a CNM because they point out all the flaws of our current way of caring for women (or might convince you to help us work towards changing the current system) -
Born in the USA by Marsden Wagner -
http://www.amazon.com/Born-USA-Broke...9854214&sr=1-1
Pushed by Jennifer Block -
http://www.amazon.com/Pushed-Painful..._bxgy_b_text_b
Journals are also a nice way to learn about an area of nursing. Some of the journals I read are the Journal of Midwifery and Women's Heath, Maternal Child Nursing (MCN), Journal of Obstetric, Gynecologic and Neonatal Nursing (JOGNN), Birth, Journal of Perinatal and Neonatal Nursing, and a few OB journals.
Don't forget the movie The Business of Being Born - available on Netflix, comes out to buy on DVD this week.
Hope that helps - good luck deciding.
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