Carl D. Anderson was a physicist who won a Nobel Prize for the discovery of the positron. He studied and taught at the California Institute of Technology (Caltech). In this interview, he discusses his impressions of J. Robert Oppenheimer, including Oppenheimer’s early struggles as a teacher. Anderson describes the work that was going on at Caltech at the time, including the groundwork that went into his Nobel-winning discovery. He also details how he turned down a role on the Manhattan Project, and the war work he did instead.