Williams has also held visiting appointments at Bowdoin College and Stanford University, as well as three grants from the National Endowment for the Humanities. He is the author of Popular Religion in America (1980), America's Religions: Traditions and Cultures (1989); and Houses of God (1997); and editor of the Encyclopedia of the American Religious Experience (1988) and the Encyclopedia of American Social History (1993). His research interests focus on the built environment and landscape of religion in America.
He received a Ph.D. in American Religious History from Yale University in 1970, 

Source: https://www.materialreligion.org/participants/williams.html