"When Breath Becomes Air" is a memoir by Paul Kalanithi, a neurosurgeon diagnosed with terminal lung cancer at the age of 36. The book explores his journey from a doctor treating patients to a patient facing his own mortality. Kalanithi reflects on the meaning of life, the practice of medicine, and the intersection of science and philosophy. The memoir is divided into two parts: the first focuses on Kalanithi's medical training and career, while the second delves into his experiences with illness and the challenges of dying. It offers profound insights into the human condition and the quest for purpose in the face of death.