Prophets of Deceit (A Study of the Techniques of the American Agitator) is a 1949 book co-written by the German sociologist Leo Löwenthal and the Polish-Jewish scholar Norbert Guterman. The authors analyze and define media appeals specific to American pro-fascist and anti-Semite agitators of the 1940s, such as the application of psychosocial manipulation for political ends. The book details psychological deceits that ideologues or authoritarians commonly used. The techniques are grouped under the headings "Discontent", "The Opponent", "The Movement" and "The Leader". The authors demonstrate repetitive patterns commonly utilized, such as turning unfocused social discontent towards a targeted enemy. The agitator positions himself as a unifying presence: he is the ideal, the only leader capable of freeing his audience from the perceived enemy. Yet, as the authors demonstrate, he is a shallow person who creates social or racial disharmony, thereby reinforcing that his leadership is needed. The authors believed fascist tendencies in America were at an early stage in the 1940s, but warned a time might come when Americans could and would be "susceptible to ... [the] psychological manipulation" of a rabble rouser. Prophets of Deceit was published by Harper and Brothers as the first in a multi-volume series edited by Max Horkheimer and Samuel Flowerman for the American Jewish Committee's "Studies in Prejudice Series". It was well received by critics and political analysts, and was considered a valuable contribution to mid-20th century studies of prejudice. Background "Studies in Prejudice Series" was a research project to produce a sociological study of prejudice in America in the 1930s and 1940s. The authors were German refugees living in the US, with first-hand experience of the Nazi regime, which imbues their work with a "tremendous vitality and a sense of relevance". During their exile from Germany, while living in Los Angeles, Max Horkheimer and Theodor W. Adorno, both members of the Frankfurt School and working in conjunction with the Institute for Social Research, undertook an expansive research study of what they saw as a shift in spirit, a worldwide movement, which "defined not only mass culture in the United States but also the administrated cultures of the Third Reich and Stalin's Soviet Union." In 1943 the Institute for Social Research partnered with the American Jewish Committee to investigate American anti-Semitism and publish a multi-volume research study. Horkheimer believed that the scrutiny had to be focused on the agitators, the manipulators, and he thought