What follows is a poignant account of his life, his quest to find meaning, his efforts to retain his humanity in the grind of becoming a doctor and, ultimately, his thoughts on dying.
As he and his wife, Lucy, grapple with whether to become parents in their remaining time together, she asks him: "Don't you think saying goodbye to your child will make your death more painful?"
In Kalanithi's childhood and college years, one can see the seeds that created this ethos.
When Kalanithi's family moved from New York to a desert town in Arizona, his mother, fearing for her children's educational prospects, obtained a "college prep reading list," which then-10-year-old Paul began to tackle.
"Books became my closest confidants," Kalanithi writes, explaining the profound themes, rich lexicon and literary quotes peppered throughout his writing.
One summer while in college, he applied for an internship at a research center as well as a job at a lakeside camp; he was accepted at both and had to choose. "In other words, I could either study meaning or I could experience it." He picked the latter.
It is no surprise, then, that Kalanithi chose the incomparably demanding field of neurosurgery. His reflection on the practice, responsibility, idealism and fallibility of medicine is a must-read for those in the field and those touched by it.