Leonard Dinnerstein, a historian whose doctoral dissertation on the 1915 lynching of Leo Frank, a Jewish factory manager, in Atlanta heralded his career as one of the nation’s foremost scholars of anti-Semitism, died on Jan. 22 at his home in Tucson. He was 84.

The cause was complications of kidney failure, his daughter, Julie Dinnerstein, said. He had spent most of his academic career at the University of Arizona in Tucson.

Professor Dinnerstein was a young scholar who had completed postgraduate course work at Columbia University in 1963 and was gravitating toward a thesis topic on political history when his wife proposed a more contemporary subject, like civil rights.

His adviser approved, he recalled, and as he was leaving the building following their meeting an acquaintance reminded him that “the Jews were involved in civil rights before it became a Negro issue,” he would later write. Another friend suggested that the topic be narrowed further to Leo Frank.