Did you know that at certain times of the month, women are inclined to dance more? Flirt more? Or that PMS may have evolved to remove boyfriends with unfit sperm? Why? Hormones. Hormones help women choose mates, produce healthy offspring, raise them successfully, and, ultimately, make better decisions. In this paradigm-shifting book, Martie Haselton explains how hormonal intelligence works - both its strengths and its weaknesses - and how women can track and understand their desires, fears and perceptions.