I've been meaning to post about this for a while, and then something on a friend's blog reminded me of it. So, for mothers who have daughters of a certain age, here is my totally uncompensated endorsement of American Girl's book The Care and Keeping of You: The Body Book for Girls.
I bought this book for G late last spring, when she started needing deodorant and I realized that other changes were probably in the offing, and it's been great. She was a bit embarrassed about it at first and wanted to read it alone in her room, but after the first two or three times through, she started showing me pages she'd dog-eared and asking me questions about what was on them. Sometime around the fourth or fifth reading, we walked into Target, and she immediately sang out, "DO YOU NEED ANY TAMPONS, MOM? HERE, I'LL HELP YOU CHOOSE SOME!" and went skipping off to the sanitary-products aisle while I followed under the amused gaze of our fellow shoppers. Since then, she's nearly read the book to pieces, and still gets it out pretty frequently to have a look at her favorite sections.
The particularly nice thing about the book, as far as I'm concerned, is that it weaves the information about bras and periods into more general discussions about personal care (exercise, sleep, bathing, etc.), so it doesn't seem like such a huge OMG puberty!! deal. It also does not mention sex or reproduction, which is a plus if you just want to have the "what's happening to your body" talk without getting into everything else. Although personally I wished there'd been a chapter on the topic, or at least a companion book, because I had to have that talk with her from scratch, and it was a challenge even for someone as un-squeamish as me. (With an only child, there's never an opportunity to have the basic "how the new baby got inside Mom" discussion, so she pretty much knew nothing.)
So anyway, there you have it. I would say the book is appropriate for ages 8-12 -- it's written at about a fifth-grade reading level, so G had no trouble reading it on her own. It does have a cartoon-style picture of a girl inserting a tampon, which seemed to disturb some of the reviewers on Amazon, but the way I look at it, if you're old enough to need the information, you're old enough to see it illustrated. Although I did decline to provide a live demonstration when G asked. I'm relaxed, but I'm not that relaxed.