In this interview, David Zierler, Oral Historian for AIP, interviews Leonard Susskind, Felix Bloch Professor of Theoretical Physics at Stanford University. Susskind recounts his childhood in the Bronx, and describes his good fortune of being the product of public education in New York from elementary school through CCNY for college. He discusses his discovery that he had a talent for physics, and the difficulties he faced convincing his father that that he would pursue this path and not join in the family plumbing business. Susskind explains the formative advice given to him by professor Harold Rothbart, and the influence of Jesse Douglas and Harry Soodak on his intellectual development as a theorist. He recounts his experience in graduate school at Cornell, where he worked under the direction of Hans Bethe calculating the ground state of infinite nuclear matter. He describes his studies under Richard Feynman and how he admired Feynman’s ability to cut through problems. Susskind discusses his teaching career at the Belfer Graduate School of Science at Yeshiva University, and he provides an intellectual history for the origins of string theory starting with Geoffrey Chew and the S-matrix of hadronic collisions, culminated in the Veneziano amplitude by Gabriele Veneziano, and he describes his contributions from there, for which he is popularly knows as one of the “fathers” of string theory. He describes joining the faculty at Stanford, he discusses the advances made by Stephen Hawking, and he asserts that our understanding of the origins of the universe remain at the primitive stage. Susskind explains why he is devoted to explaining physics concepts to broad-based audiences, and he explains what he sees as the most critical threats posed by the Trump administration. In part II, the interview returns to Susskind’s early years, and he recounts his father’s support for civil rights, and how this influenced his own politics in the 1960s. He describes his goals in his debate with Lee Smolin and engages in some of the spiritual and metaphysical implications that can arise from studying the universe. At the end of the interview, Susskind reviews, over the course of his career, the ways string theory has, and has not, contributed to efforts to unify all theories of physics, and he affirms that he more closely aligns with Einstein’s approach not to tolerate a clash of physics principles, over that of Niels Bohr.