Paul Sudhir Arul Kalanithi (April 1, 1977 – March 9, 2015) was an American neurosurgeon and writer. His seminal work, When Breath Becomes Air, is a memoir that delves into his life and battle with stage IV metastatic lung cancer. Posthumously published by Random House in January 2016, the book has received critical acclaim, notably making it to The New York Times Non-Fiction Best Seller list for multiple weeks.

Kalanithi's journey began in Kingman, Arizona, where he grew up before attending Stanford University and graduating in 2000 with a B.A. and M.A. in English Literature and a B.A. in Human Biology. His academic pursuit took him across the pond to the University of Cambridge, where he earned an M.Phil in History and Philosophy of Science and Medicine. Kalanithi's passion for medicine led him to the Yale School of Medicine, where he graduated cum-laude in 2007, winning the Lewis H. Nahum Prize for outstanding research and clinching membership in the Alpha Omega Alpha medical honor society. After medical school, he returned to Stanford for residency training in Neurological Surgery and a postdoctoral fellowship in neuroscience, amassing over twenty scientific publications during this period.