Thomas Greenslade received an A.B. in physics from Amherst College in 1959 and a doctorate in experimental low temperature physics from Rutgers University in 1965. From 1964 to 2005 he taught physics at Kenyon College in Gambier, Ohio. His research deals with early physics teaching apparatus, and in support of that he has a large web site, a private museum wing to his house, and an ongoing series of 624 illustrations of early apparatus in American Journal of Physics. Since retiring he has continued writing and lecturing about early apparatus. He has been fascinated by Lissajous figures and the harmonographs used to draw them since his undergraduate days. This has resulted in a series of articles about these fascinating devices, and he has built several of them to demonstrate them to others. He has 289 publications in The Physics Teacher, American Journal of Physics, Rittenhouse and Physics in Perspective, and has given 223 talks at AAPT meetings and physics department seminars. He served for 16 years on the Committee on the History and Philosophy of Physics, and was chair for four two-year terms. The American Association of Physics Teachers awarded him with a Distinguished Service Citation in 1987, and made him a Fellow in 2014. In 2002 he was listed as one of the 75 most influential physics teachers and physicists in the United States. He is now a past member of the AAPT Committee on the Interests of Senior Physicists. His entry for the 2007 AAPT Apparatus Competition won first place. In 2015 he was made a Fellow of the American Physical Society.