This volume presents the evolution of the authors' ideas about estrogen action and its modulation by a new group of drugs called SERMs (Selective Estrogen Receptor Modulators). The pioneering SERMs — tamoxifen and raloxifene — are known to have saved the lives of millions of women around the world and improved the health of millions more. Estrogen is the central hormone of women's health and reproduction. The book is a journey through 40 years of discovery and success in advancing women's health, with the prospect of improved innovation through medicinal chemistry for the future.