This book opens the door to the frequently obscure world of scientific discovery, not just to document discoveries, but also to explain how these discoveries come about. As an example, it tells, in an accessible way, the exciting story of the important discovery of a protein called RANKL, which led to the development of a drug therapy that is used worldwide to treat osteoporosis, cancer and other diseases. The story will be of interest to informed laypersons, students, and people with osteoporosis.