Rosenbaum spent more than ten years doing research on Adolf Hitler including travels to Vienna, Munich, London, Paris, and Jerusalem, interviewing leading historians, philosophers, biographers, theologians and psychologists.
Some of those interviewed by Rosenbaum included Daniel Goldhagen, David Irving, Rudolph Binion, Claude Lanzmann, Hugh Trevor-Roper, Alan Bullock, Christopher Browning, George Steiner, and Yehuda Bauer.
In Explaining Hitler, Ron Rosenbaum also recounted in detail the previously little-reported story of the efforts of anti-Hitler journalists at the Munich Post who, from 1920 to 1933, published repeated exposés on the criminal activities of the National Socialist German Workers Party (i.e. the Nazis).
Matthew Ricketson, coordinator of the Journalism program at RMIT University's School of Applied Communication in Melbourne, Australia, called this book "a brilliant piece of research".
In December 2015, Rosenbaum published the article "Thinking the Unthinkable", in which he expresses his view that there exists a frightening possibility that Israel might not survive as a nation.