Peggy Hamburg discusses her distinguished career as an internationally recognized leader in science, medicine, and public health. Hamburg served as the twenty-first commissioner of the U.S. Food and Drug Administration, the foreign secretary of the National Academy of Medicine, and the founding vice president and senior scientist at the Nuclear Threat Initiative, and currently chairs the Harvard Medical School board of fellows and serves on numerous other nonprofit boards and advisory councils. Lessons Learned is a roundtable series, open to term members and younger life members, which features distinguished speakers who reflect on their career experiences, the choices they made along the way, and the lessons they have learned from them.