More than just a brilliant physicist, Richard Feynman was also a larger-than-life character whose enthusiasm, boundless curiosity, and mischievous sense of humor made him a dynamic lecturer and memoirist, as well as leading him to pick locks and crack safes for fun. But the very traits that continue to charm science fans today also brought him to the attention of the FBI—and now, with the help of a recent Freedom of Information Act request, we know all the dirt they gathered on the bongo-playing physicist.