Greg M. Epstein (born 1977) is an American Humanist chaplain at Harvard University and the Massachusetts Institute of Technology who is the president of the Harvard Chaplains Organization.[1][2] He is an ordained Humanist rabbi, and has been influential in American humanism as a blogger, spokesperson, adviser and author of the New York Times bestseller Good Without God: What a Billion Nonreligious People Do Believe. Epstein was an expert on the first three seasons of the reality show "Married at First Sight."[3][4]