According to Roger Griffin, Gregor wrote an influential early comprehensive survey of existing theoretical models of fascism.Roger Griffin, "Old Hat, New Bird," Review of Politics (2000), 62: 844–847 . Per Andreas Umland writing for The American Historical Review in 2013, "A. James Gregor has, for half a century, been one of the major makers and shapers of the discipline of comparative fascism."See review by Andreas Umland in The American Historical Review (2013) 118(3) p. 1484. . Sean Kennedy in Canadian Journal of History said in 2013, "Over a long and distinguished career A. James Gregor has advanced some controversial interpretations of political ideologies. In particular, he holds that the Italian Fascist regime is best understood as a "developmental dictatorship," distinct from Nazism in key ways; a thesis that has proven surprisingly influential since 1945."See review by Sean Kennedy in Canadian Journal of History (2013) 48(3) p. 575. Shortly after Gregor's death an extensive critical survey of his works on Fascism was published as a monograph by social scientist Phillip Becher.Phillip Becher, Faschismusforschung von rechts: A. James Gregor und die ideozentrische Deutung des italienischen Faschismus, Köln: PapyRossa, 2020. In 2021, Italian historian Antonio Messina edited a collected volume on Gregor's thought and works.Antonio Messina (edited by), Comprendere il Novecento tra storia e scienze sociali. La ricerca di A. James Gregor, preface by Alessandro Campi, Rubbettino, Soveria Mannelli, 2021.
