Today we focus on the Soviet nuclear program with Thomas Cochran. Tom directed nuclear disarmament projects at the Natural Resources Defense Council from 1973 until his retirement in 2016. He has received numerous awards for his work on nuclear disarmament, including the public service award from the Federation of American Scientists and the Szilard Award from the American Physical Society, both in 1987. Tom was elected Fellow of the American Association for the Advancement of Science in 1989, and, due to his work, the Natural Resources Defense Council received the AAAS Scientific Freedom and Responsibility Award that same year. Today we discuss the Soviet nuclear weapons program, from Stalin finding out about the bomb to Gorbachev’s unilateral test moratorium. Tom played key roles in the seismic monitoring experiment, visits by US Congressional delegations to sensitive Soviet military installations, the Black Sea experiment, and other adventures in nuclear de-escalation.