Explaining Hitler: The Search for the Origins of His Evil is a 1998 book by journalist Ron Rosenbaum which tells of Rosenbaum's struggles with the "exceptionalist" character of Adolf Hitler's personality and impact on the world or, worse from his point of view, his struggle with the possibility that Hitler isn't an exception at all, but on the natural continuum of human destructive possibility.
For example, Rosenbaum discusses a theory advanced by Rudolph Binion, a professor at Brandeis University, who believes that Hitler's personality was moulded or deformed by witnessing as a child the suffering of his mother, Klara, who died of breast cancer.
Binion says that Hitler's mother was treated by a Jewish doctor, Eduard Bloch, with the standard remedy of the time, iodoform. Bloch was excessive in his prescribed dosages of iodoform, however, and the caustic and scarring effects of this chemical exacerbated his patient's suffering. Binion believes Hitler's rage at this was transferred to the Jewish people as a whole.