I first became aware of the information contained in this book way back in 1999 or so, though it was through a website or web forum. I used this information as my birth control for about 5 years. Using this knowledge, both times that I had unprotected sex while during my fertile period I got pregnant and outside of those two times, I did not get pregnant. I wasn't intentionally trying to get pregnant, but I also wasn't trying very hard to not conceive. This knowledge is useful for both avoiding pregnancy and increasing fertility and I highly recommend it in an era where there is the possibility that women will lose access to other forms of contraception, plus there is growing knowledge of the side effects of hormonal birth control.

Every single woman should own this book, in my opinion. Even if you, as a woman or vagina/uterus-owner, aren't sexually active with men, you need this book to understand more than the vast majority of ob/gyns about the menstrual cycle and how your reproductive parts work. It also has some information on the science and psychology of female sexual pleasure, though it is more of an overview.

The author of this book also has published a book with the menstrual cyle information & puberty geared toward teenagers, though I haven't read it. If you read my review & are searching for a book chiefly about the menstrual cycle & charting it & understanding it for teenagers, or this very, very fat book is just too many pages, you should go check that book out. ( )

Fascinating book. Female hormones / biology are both complicated and interesting in all kinds of ways I wouldn't have expected. Book-length content also goes into more and more useful detail than I've been able to find anywhere on the internet, again demonstrating that internet content may be broad but it is also extremely shallow. ( )