In this revealing work, a medical writer and an internationally-known physician team up to explain the controversy over medicine prescribing estrogen for perimenopausal women in the United States, and to detail why progesterone is actually a far more effective, and a far less risk-ridden, approach. Citing long-standing and emerging research, patient vignettes, and personal experience, endocrinologist Jerilynn Prior and writer Susan Baxter tell us how false beliefs on estrogen became entrenched in U.S. medicine and culture, and why business and politics have played a role in this erroneous thinking. Like most women in Europe, Prior's patients find progesterone the key to dealing with a life cycle transition that, contrary to Western medicine, these authors do not see as a disease. Challenging medical orthodoxy, this work presents arguments and evidences both women and doctors will find compelling.