Relentless is the compelling story of how Mount Sinai Health System mobilized to confront the COVID-19 pandemic. The book is based on unprecedented access to internal hospital documents and more than 100 candid interviews with the leaders of Mount Sinai’s hospitals and the Icahn School of Medicine at Mount Sinai. It contains accounts of physicians and nurses on the front lines who pushed themselves to the brink to save lives; of research scientists who urgently worked to decipher the virus and find ways to counter it quickly and safely; and of the brave patients, staff members, and medical students who summoned their reserves of energy, compassion, and courage to fight the pandemic.