The book has many stories which are lighthearted in tone, such as his fascination with safe-cracking, studying various languages, participating with groups of people who share different interests (such as biology or philosophy), and ventures into art and samba music.

Other stories cover more serious material, including his work on the Manhattan Project (during which his first wife, Arline, died of tuberculosis) and his critique of the science education system in Brazil.

The section "Monster Minds" describes his slightly nervous presentation of his graduate work on the Wheeler–Feynman absorber theory in front of Albert Einstein, Wolfgang Pauli, Henry Norris Russell, John von Neumann, and other major scientists of the time.

[2] The final chapter, "Cargo Cult Science," was adapted from Feynman's 1974 commencement address at the California Institute of Technology,[3] in which he cautioned graduates not to minimize the weaknesses of their research in the pursuit of a preferred conclusion.

He drew an analogy to the cargo cult phenomenon in the South Pacific Ocean in which, as he understood it, islanders built a mock airstrip to cause airplanes loaded with imported goods to land.