In this interview Professor Leo Mandelkern begins with his early years in New York City and his undergraduate education at Cornell University. This is followed by his service as a meteorologist during World War II. In the central portion of the interview, Mandelkern describes his graduate education at Cornell, including his association with J. G. Kirkwood, Franklin Long, and Paul Flory. Particular emphasis is given to his postdoctoral work with Flory and collaborative work with Harold Scheraga. The details of Mandelkern's career at the National Bureau of Standards include Bureau operations and management in the 1950s. The interview continues with more recent work at Florida State, including students and post-docs. It concludes with comments on methods of solving scientific controversies, especially as it relates to his role in the problem of the folded chain.