Scientists and media outlets have hailed ketamine, which the Food and Drug Administration approved in 2019 for the treatment of depression, as quite miraculous. This book in the MIT Press, Essential Knowledge series charts the rise of a drug that has been used for fifty years and has been repurposed as a treatment for depression. Its prior uses include a military anesthetic from the Vietnam War and a common club drug. Leading neuropharmacology researcher Bita Moghaddam explains ketamine’s biochemistry and clinical applications and recently revealed antidepressant properties for readers who aren’t experts.