Peter Hayes is Professor of History and German and Theodore Zev Weiss Holocaust Educational Foundation Professor of Holocaust Studies Emeritus at Northwestern University. W. W. Norton & Co. published his new book, Why? Explaining the Holocaust, on January 17.

‘Beware the Beginnings’

Hitler was not that popular when he first took office, but the Nazis quickly changed that, for the simple reason that power magnifies the ideas of those who hold it.