Book excerpt: This issue of Dermatologic Clinics, guest edited by Dr. Neil S. Sadick, will cover a number of key topics related to Hair. This issue is one of four each year selected by longtime series Consulting Editor, Dr. Bruce Thiers. Articles in this issue include: Clinical patterns of hair loss in men: Is DHT the only culprit?; Understanding causes of hair loss in women; New diagnostic tools to evaluate hair loss; FDA approved treatments for hair loss; Frontal fibrosing alopecia: is it the new epidemic?; Scarring alopecia: diagnosis and new treatment options; Central centrifugal alopecia: challenges and treatments;Alopecia areata: new treatment options including JAK inhibitors; Trichoceuticals; Platelet-rich plasma and cell therapy: the new horizon in hair loss treatment; Energy-based devices for hair loss; Follicular unit extraction for hair transplantation: an update; Automated devices for hair transplantation; and Combination approaches for combatting hair loss.