The book is an exploration of the biology and pathophysiology of cortisol, a crucial hormone for survival, from the perspective of a multidisciplinary team of international experts. From presenting the current state of knowledge in the field of hormone physiology to discussing aspects related to cortisol measurement methods, the book raises a series of challenges for both endocrinologists and physicians from other specialties. It addresses interesting topics such as the role of enzymes involved in adrenal steroidogenesis, the connection between cortisol and obesity, and the role of hormone therapy in multiple sclerosis.