"When Breath Becomes Air" is an autobiography of a doctor who became a patient after being diagnosed with Stage IV lung cancer. At first it starts with Kalanithi in good health and working towards his goals and becoming a neurosurgeon. He is highly motivated and interested in pursuing mortality and what makes a life meaningful. During this period he is the one who guides terminally ill patients and families through the changes in their lives and must help them come to terms with the decisions they need to make. Then suddenly, the roles are reversed upon him and Kalanithi becomes the patient and he is the one being guided through the changes and decisions. The sudden change is shocking, yet he manages to work through it. In the final stages of his life, he begins to reflect his life and wonder what to do with a single day. By the end, it seems he has come to some form of acceptance of his own mortality. Yet throughout the autobiography is the thoughtfulness and the theme of mortality and death.
At first, he wanted to "uncloak death" and stare at it unblinking. But when he faced his own mortality, he found that it seemed very different. Death once so surreal had suddenly become his reality. And he had to navigate through it without any experience. He found himself lost and unsure of what directions to take. During this time, he began to realize what his patients had gone through and the true weight of mortality.
But what really sticks is this quote: "Years ago, it had occurred to me that Darwin and Nietzsche agreed on one thing: that defining characteristic of the organism is striving."