When I was very young, I thought my father knew everything. Indeed, a prominent magazine once declared him “The Smartest Man in the World.” Upon hearing this, his mother threw up her hands and exclaimed, “If Richard is the smartest man in the world, God help the world!” My father was the first one to laugh.

Feynman at home, 1966 Courtesy of Michelle Feynman and Carl Feynman

As I grew older, I began to see only what my father didn’t know, and came to think I was the one with all the answers. He would ask me questions whose answers I found to be painfully obvious, such as, “Hey, Michelle, where do we keep the spoons around here?” I discovered the real truth in my late teens. My father was a wise man with a tremendous appetite for life, an insatiable curiosity about how the world works, and a great aptitude for teaching.

Here are the basic facts of his life: Richard Phillips Feynman was born in New York City in 1918 and grew up in Far Rockaway, Queens. He attended MIT and Princeton University. In 1942 he married his high-school sweetheart, Arline Greenbaum, even though she was ill with tuberculosis, and joined the Manhattan Project, where he became a group leader. Arline died in 1945. In 1950 he joined the faculty of Caltech and spent the remainder of his career there. He was an adventurer who made a hobby of cracking safes, who played bongo drums for a San Francisco ballet, and who decided to learn to draw in his forties—and became remarkably good at it. He married my mother, Gweneth Howarth, in 1960. My brother, Carl, was born in 1962, and I was adopted in 1968.

Though he remained forever ambivalent about it, his most public achievement came in 1965, when he won the Nobel Prize in Physics, sharing it with Julian Schwinger and Shin’ichiro Tomonaga for their work in quantum electrodynamics, a description of how subatomic particles interact. In 1986, he was again in the public eye, this time working on the commission investigating the explosion of the space shuttle Challenger. He died in 1988 after a long battle with abdominal cancer. Caltech held two memorial services, and the auditorium quickly reached capacity both times.

Despite his success, my father encouraged an irreverent attitude toward himself. Our dinner conversations were full of tales about mistakes he made during the day: losing his sweater, having conversations with people and not remembering their names. On Sunday mornings, he would often forgo reading the newspaper in favor of a wild hour of loud, often discordant music, drumming, and storytelling with my brother and me. When it was his turn to drive the car pool to elementary school, he would pretend to get lost. “No, not that way!” all the kids would scream. “Oh, all right. Is it this way?” and he would turn the wrong way again. “Nooooooo!” we would yell in utter panic.

Of my father’s many skills, this willingness to play the fool—and to let me think he could be outfoxed by my clever thinking—was the one that shaped my childhood more than any other. This is also the key, in my mind, to his success as a teacher. Never condescending, he had a knack for breaking problems down to a seemingly simplistic level and then allowing his students to be the geniuses who figured out the solutions.

These memories and more came flooding back to me when I began sorting through twelve filing-cabinet drawers of papers from the Caltech Archives. As I delved into his correspondence, I was completely captivated. In his written work my father is articulate, insightful, considerate, humble, funny, and charming. These letters are testimony to his skill and desire to be plainly understood—and, of course, to his passion and curiosity about the world. Again, his own words, written to a young student seeking advice, explain it best: “You cannot develop a personality with physics alone, the rest of life must be worked in.”

Scientist and educator

Richard Feynman’s influence as a teacher rivaled his importance as a researcher. The Feynman Lectures on Physics are a treasured resource for many students entering the field. Late in his career, he was still honing his craft, as illustrated in a 1984 letter to Cornell physicist David Mermin: “All my mature life I have been trying to distill the strangeness of quantum mechanics into simpler and simpler circumstances. I have given many lectures of ever increasing simplicity and purity. I was recently very close to your description . . . when your ideally pristine presentation appeared. . . .”

Teaching at Caltech, 1955 Courtesy of Caltech

Feynman to high-school student Frederich Hipp, April 5, 1961

To do any important work in physics a very good mathematical ability and aptitude are required. Some work in applications can be done without this, but it will not be very inspired. If you must satisfy your “personal curiosity concerning the mysteries of nature” what will happen if these mysteries turn out to be laws expressed in mathematical terms (as they do turn out to be)? You cannot understand the physical world in any deep or satisfying way without using mathematical reasoning with facility. . . .

If you have any talent, or any occupation that delights you, do it, and do it to the hilt. Don’t ask why, or what difficulties you may get into. If you are an average student in everything and no intellectual pursuit gives you real delight, then I don’t know how to advise you. . . .

Bomb builder

During World War II, Feynman worked on the Manhattan Project and tended to his wife, Arline, who was ill with TB. He amused himself by noting security lapses in the top-secret project; he easily cracked locks and safes at Los Alamos. “The key to my interest in all this is probably because I like puzzles so much,” he wrote to Arline. “Each lock is just like a puzzle you have to open without forcing it. But combination locks have me buffaloed. You do too, sometimes, but eventually I figure out you.”

He struggled to keep Arline in good spirits as her health declined. “This time will pass—you will get better. You don’t believe it, but I do,” he wrote on June 6, 1945. She died 10 days later.

Arline Greenbaum circa 1939, before their marriage. Courtesy of Michelle and Carl Feynman

Feynman to his wife, Arline, April 3, 1945

I love you. You are a strong and beautiful woman. You are not always as strong as other times but it rises and falls like the flow of a mountain stream. I feel I am a reservoir for your strength--without you I would be empty and weak like I was before I knew you--but your moments of strength make me strong and thus I am able to comfort you with your own strength when your stream is low. . . .

We have a regular gestapo up here. They took a guy for over an hour in a smoke filled room with men sitting around in the dark--just like in the movies--firing questions at him to prove he was a Communist. They didn’t succeed--because he wasn’t. The poor guy couldn’t work good the next day because they got him out of bed the night before. They claim they are trying to keep spies out of this place. It is dopey, because they leave the gates open at night often by mistake. Don’t get scared tho they haven’t found out that I am a relativist yet!

Feynman in 1944. Courtesy of Michelle and Carl Feynman

Public intellectual

Feynman became the pivotal player on the team investigating the Challenger space shuttle disaster. A simple experiment cut through a great deal of ambiguous testimony. He placed a piece of an O-ring (a gasket in the shuttle booster rockets) in ice water to simu-late the temperatures on the day of Challenger’s launch. The material became brittle, dramatically demonstrating the cause of the accident. In a letter to the chairman of the investigation, Feynman explained his findings: “The large number of negative observations are a result of the appalling condition the NASA shuttle program has gotten into.”

Testifying about the Challenger space shuttle accident, 1986. Courtesy of Caltech

Feynman to Gweneth and Michelle Feynman, February 12, 1986

The following was written during Feynman’s stint on the commission investigating the Challenger space shuttle accident.

You, Gweneth, were quite right--I have a unique qualification--I am completely free, and there are no levers that can used to influence me--and I am reasonably straight-forward and honest. There are exceedingly powerful political forces and consequences involved here. . . . I disregard them all and proceed with apparent naive and single-minded purpose to one end, first why, physically the shuttle failed, leaving to later the question of why humans made apparently bad decisions when they did. . . .

Tomorrow at 6:15 we go by special airplane (two planes) to Kennedy Space Center to be “briefed.” . . . My guess is that I will be allowed to do this overwhelmed with data and details, with the hope that so buried with all attention on technical details I can be occupied, so they have time to soften up dangerous witnesses etc. But it won’t work because (1) I do technical information exchange and understanding much faster than they imagine, and (2) I already smell certain rats that I will not forget because I just love the smell of rats for it is the spoor of exciting adventure. . . .