"When Breath Becomes Air" is a memoir by neurosurgeon Paul Kalanithi, who was diagnosed with terminal lung cancer at the age of 36. The book recounts his journey through medical school, residency, and his battle with cancer, exploring themes of life, death, and the meaning of existence. The excerpts highlight Kalanithi's reflections on his identity as a doctor and a patient, his relationship with his wife and family, and his philosophical exploration of the nature of mortality. The text also delves into his struggles with the emotional and physical toll of his illness, his desire to return to surgery, and his ultimate decision to embrace his fate.