Perfectly Reasonable Deviations from the Beaten Track

A collection of Richard P. Feynman's letters, edited and annotated by his daughter Michelle Feynman, with a foreword by Timothy Ferris. The letters span his career, opening with a brief note home written early in his graduate studies and closing, decades later, with a reply to a stranger who had asked for his advice; many appear in print for the first time. Correspondents include the scientists Victor Weisskopf, Edward Teller, James Watson and Stephen Wolfram, alongside fans, students, family members and cranks. Subjects range from the Manhattan Project, quantum physics and the Challenger investigation to grade-school textbooks, his love for his wife and how best to approach a problem.

Naval Ravikant said in a podcast interview that he had been reading it while also rereading Genius.