Hans Bethe, Part 2: Bethe was a German-American physicist and Nobel Prize winner who led the Theoretical Division at Los Alamos during the Manhattan Project and later had an important role in the development of the hydrogen fusion bomb. In this interview, Bethe explains why he opposed developing the hydrogen bomb and provides insight into the General Advisory Committee's decision to pursue it. He also discusses nuclear proliferation, which scientists may have influenced J. Robert Oppenheimer's thoughts on the hydrogen bomb, and the challenges of developing the H-bomb.

Norris Bradbury was an American physicist and director of the Los Alamos National Laboratory from 1945-1970. During the Manhattan Project, Bradbury directed the implosion field test program and helped prepare the "Gadget" for the Trinity test. In this interview, Bradbury explains why he was selected to work at Los Alamos, and discusses his work on the plutonium implosion bomb. He recalls his interactions with Manhattan Project leaders J. Robert Oppenheimer, George Kistiakowsky, and Admiral Deak Parsons. Bradbury watched over the "Gadget" at the top of the Trinity test tower to ensure that no one "monkeyed" with it. He remembers his surprise when Oppenheimer picked him to take over as director of the laboratory, and the challenges he had to overcome to keep the lab running.

John De Wire was a physicist who was recruited by J. Robert Oppenheimer to work on the Manhattan Project in Los Alamos. In this interview, De Wire discusses how he was recruited, the move to Los Alamos, the organization and administration at Los Alamos, and the unusual speed with which scientists could procure items. He explains how he came to work at Princeton, and his involvement after the war in opposing Lewis Strauss's nomination for Secretary of Commerce. He recalls what made Oppenheimer such an effective leader.

German-American chemist Gerhart Friedlander fled Nazi persecution in 1936. He studied at the University of California with Glenn Seaborg, earning his Ph.D. in nuclear chemistry in 1942. The following year, he joined the Manhattan Project at Los Alamos and became group leader of the radioactive lanthanum group in the Chemistry Division. After World War II, Friedlander worked at Brookhaven National Laboratory for many years and chaired the Chemistry Department. In this interview, he describes how Seaborg secretly involved him in plutonium work and how his group investigated the implosion method for the plutonium bomb. He also recalls winning a bet with Enrico Fermi.

Dr. Clarence Larson, a chemist, began working under Ernest O. Lawrence in his lab at the University of California, Berkeley in 1942. In 1943, he moved to Oak Ridge and was appointed head of technical staff for the Tennessee Eastman Corporation. He later served as director of Oak Ridge National Laboratory and as a commissioner on the U.S. Atomic Energy Commission. During the Manhattan Project, Larson designed a process to recover and purify uranium deposits from the walls of Calutron receivers at the Y-12 Plant. In this interview, he explains the importance of this innovation in producing enough enriched uranium for an atomic bomb. He also describes the challenges encountered in the Y-12 Plant's early days, as well as Lawrence's leadership skills and unyielding confidence.

Donald Ross worked on the Manhattan Project at the University of California-Berkeley and the Y-12 Plant for Tennessee Eastman. In this interview, Ross discusses supervising "Calutron girls" at Y-12. He explains how the electromagnetic separation process for separating uranium isotopes worked, and recalls the tight security at Oak Ridge. Ross also describes the social life at Oak Ridge, meeting his wife, and the terrible food in the mess halls. He discusses his views on dropping the bomb on Japan and how his thoughts have changed over time.

Ernest Tremmel was a civil engineer who worked on the Manhattan Project for the Army Corps of Engineers, as a purchasing officer. He went on to work for the Atomic Energy Commission (AEC) for many years and as a nuclear energy consultant. In this interview, Tremmel discusses the secrecy of the Manhattan Project and how he learned the goal of the project. He recalls interacting with General Leslie R. Groves, Admiral Hyman Rickover, and other AEC commissioners as well as directors of energy companies. Tremmel explains what made this period, and the quest to build nuclear reactors, so exciting. He also remembers witnessing a nuclear bomb test after the war.

Harry Allen and Robert Van Gemert worked in procurement at Los Alamos during the Manhattan Project. In this interview, the pair discusses getting ready for the Trinity test, the challenges of using Jumbo, and how materials were transported safely and secretly in and out of Los Alamos. They remember helping to acquire the lead-lined tanks used to transport scientists to the blast zone after the Trinity test. Allen and Van Gemert also discuss the dormitories at Los Alamos, how the Town Council handled problems, and the secrets of PO Box 1663. They recall their interactions with leading scientists including Emilio Segre, Enrico Fermi, and Edward Teller.