Daniel A. Greenberg (born c. 1934), one of the founders of the Sudbury Valley School, has published several books on the Sudbury model of school organization, and has been described by Sudbury Valley School trustee Peter Gray as the "principal philosopher" among its founders. He is a former physics professor at Columbia University, and is described by Lois Holzman as the school's "chief 'philosophical writer'".
^Gray, Peter and David Chanoff (February 1986). "Democratic Schooling: What Happens to Young People Who Have Charge of Their Own Education?". American Journal of Education (The University of Chicago Press) 94 (2): 182–213. JSTOR1084948. "The principal philosopher among the group of parents and others who founded SVS was Daniel Greenberg, a wide-ranging scholar who had previously taught physics and the history of science at Columbia University."