Given the sheer tonnage of books already devoted to the Nazis and Hitler, you might assume that everything interesting, terrible and bizarre is already known about one of history’s most notorious regimes and its genocidal leader. Then along comes Norman Ohler, a soft-spoken 46-year-old novelist from Berlin, who rummages through military archives and emerges with this startling fact: The Third Reich was on drugs.

All sorts of drugs, actually, and in stupefying quantities, as Mr. Ohler documents in “Blitzed: Drugs in Nazi Germany,” a best seller in Germany and Britain that will be published in the United States by Houghton Mifflin Harcourt in April. He was in New York City last week and sat for an interview before giving a lecture to a salon in a loft in the East Village, near Cooper Union.

“This is actually my old neighborhood,” he said, sipping grape juice on a sofa. “I lived around here when I wrote my first novel, a detective story.”

Mr. Ohler fell back on his interest in sleuthing during the five years it took to research and write “Blitzed.” Through interviews and documents that hadn’t been carefully studied before, he unearthed new details about how soldiers of the Wehrmacht were regularly supplied with methamphetamine of a quality that would give Walter White, of “Breaking Bad,” pangs of envy. Millions of doses, packaged as pills, were gobbled up in battles throughout the war, part of an officially sanctioned factory-to-front campaign against fatigue.