Allusions

Kalanithi's early education was in literature, and in the course of the personal narrative he alludes to a great many works without elaborating on their content or meaning. Those works include Hamlet, Brave New World, The Count of Monte Cristo, Robinson Crusoe, Ivanhoe, The Prince, "To His Coy Mistress," Le Morte D'Arthur, Don Quixote, The Last of the Mohicans, The Waste Land, Satan, How We Die, and others. He includes epigraphs before each section, quoting from the Bible, T. S. Eliot's "Whispers of Immortality," and Montaigne's "That to Study Philosophy Is to Learn to Die." His wife Lucy also includes an epigraph to her epilogue, quoting a poem by Emily Dickinson.

One important allusion is to Religio Medici or The Religion of a Doctor, which was published in 1643 and written by Thomas Browne. It's a memoir in the form of a spiritual meditation on the Christian virtues of faith, hope, and charity. It was written in two parts and included Browne's thoughts on the existence of hell, the resurrection, the Last Judgment, and other tenets of Protestantism. Both Verghese (who wrote the foreword to When Breath Becomes Air) and Kalanithi allude to it—the former to give the readers a taste of Kalanithi's style, and Kalanithi in his recollection of the death of Shep Nuland, a former teacher of his. Upon her deathbed, Nuland quotes Browne: "With what strife and pains we come into the world we know not, but 'tis commonly no easy matter to get out of it." This insight convinces Kalanithi that he must "bear witness to the twinned mysteries of death."

Metaphor

Kalanithi's writing is rich and musical, and he makes frequent use of metaphor. In one, he writes of Lucy leaning her head on his shoulder, eliminating the physical and metaphorical distance between them. In another, he describes himself as a "prophet returning from the mountaintop" with news that a new mother has delivered a healthy baby girl. These metaphors enrich the narrative and humanize the often dehumanizing practice of medicine.

Personification

In part 2, not long after his diagnosis, Kalanithi personifies Death, writing that the dark specter was "paying a personal visit" after the years of purely professional encounters they'd had while Kalanithi was a student and resident. This personification, in addition to making death look human, personalizes illness, giving Kalanithi firsthand experience of something he'd witnessed countless times.

Simile

In one simile, Kalanithi writes that, when he received his diagnosis, it "felt like someone had just firebombed the path forward," making the future bleak and unforeseeable. In another, he describes the process of deciding what mattered to him most in the wake of his diagnosis, writing, "It felt like someone had taken away my credit card and I was having to learn how to budget." These similes make it easier for the reader to relate to his personal experiences.

Style

In his foreword to When Breath Becomes Air, bestselling author and physician Abraham Verghese writes that "Paul's writing was simply stunning. He could have been writing about anything, and it would have been just as powerful. But he wasn't writing about anything—he was writing about time and what it meant to him now, in the context of his illness." Verghese likens Kalanithi's prose to that of Galway Kinnell's musical prose poems. He alludes to Thomas Browne, author of Religio Medici, a dense personal testament written in 1642, with the "archaic spellings and speech" of the times. Paul Kalanithi's writing is formal without being stiff and startles readers with its honesty and its insights into the human experience. Verghese writes, "there was an honesty, a truth in the writing that took my breath away."