Norman Ohler's findings risked shaking up accepted academic beliefs about the Nazis. "Once I immersed myself in the archives, I felt an immediate thrill. I read extraordinary documents that detailed heavy drug use at all levels of the Nazi army and government, and realised that this had not been widely discussed before. And when I actually got down to writing Blitzed, I felt relieved. I joyfully navigated my narrative within this tightly framed genre and for once spared myself from wandering endlessly through the infinite terrain called 'a novel'. Little did I know what I was getting myself into." In this piece for the Guardian, the historian recalls his excitement on discovering records of Nazi Germany’s deep involvement in drugs — and the hornets’ nest his book Blitzed stirred up.