On the verge of completing a decade's worth of training as a neurosurgeon, Kalanithi was diagnosed with stage IV lung cancer. Just like that, the future he and his wife had imagined evaporated. Kalanithi chronicles his transformation from a naïve medical student into a neurosurgeon at Stanford working in the brain, the most critical place for human identity, and finally into a patient and new father confronting his own mortality.