A look inside Feynman’s calculus notebook

One of the most unusual artifacts at the Niels Bohr Library & Archives in College Park, Maryland, is a small green notebook once owned by Richard Feynman. It contains handwritten notes he compiled as a high school student in the early 1930s, on a book called Calculus for the Practical Man. We usually think of Feynman as an impish twenty-something prodigy at Los Alamos or as the celebrated Caltech professor who enthralled undergraduates with his lectures and stories. But Feynman was once a teenager—and not even he was born knowing calculus.

In the 1930s it would have been unusual for a high school to have a calculus instructor, and trigonometry was the highest level of math taught at Feynman’s Far Rockaway High School in New York. Math professor James Edgar Thompson’s Practical Man series of self-instruction books seemed like just the way to learn more. Thompson told readers that the series was for those “who wish to obtain a practical mastery of some of the more usual and directly useful branches of the science without the aid of a teacher.”

In a 1966 interview with historian of science Charles Weiner, conducted and archived by the Center for History of Physics , Feynman said that he started with Algebra for the Practical Man, which he found easy. He was unimpressed with Trigonometry for the Practical Man and said he “didn’t find it useful or interesting.” Calculus for the Practical Man, however, created more lasting memories. His father was perplexed by the book, and as Feynman recalled, “this was rather a shock to me. . . . It was the first time I realized that I could understand what he couldn’t understand.”

Feynman’s notes closely follow the text of Calculus for the Practical Man. Feynman often used shorthand, but he copied diagrams and formulas carefully as he made his way through the book and tried to master its concepts. The notes cover the entire contents of the book—Feynman quite literally read Calculus for the Practical Man from cover to cover. He also compiled a table of contents for the notebook, which enabled him to find the relevant sections of his notes more easily later.

Feynman’s calculus notes illustrate one of the famous physicist’s defining qualities: his insatiable curiosity. His famous autobiographical anecdotes often involve him learning about subjects ranging from Mayan hieroglyphics to bongo drums and cat anatomy. When he found a subject that interested him, he was not about to wait for the right teacher to come along; he was determined to master it himself.

Both the Niels Bohr Library and the Center for History of Physics are part of the American Institute of Physics, which publishes Physics Today.