In the past year, I've read more than a dozen books about Hitler, the Nazis, and the rise and fall of the Third Reich (including The Rise and Fall of the Third Reich, by William Shirer, 1960).

That's about 8,000 pages filled with words about genocide, atrocity, military history, man's inhumanity to man—not to mention a dozen separate, and frequently conflicting, accounts of the man who most shaped the 20th century. Here are a few of the things I learned.

(1) Never read about Hitler on the bus. Unless, that is, you're looking for conversations with beady-eyed homeless guys who stare at you sideways and mutter, "He was right about a lot of things, you know." Followed by: "So... where are you getting off?"

(2) Because Hitler is such an impossible subject (simultaneously the inhuman embodiment of evil and an actual, if unknowable, human being), the best biographies have a Unifying Theory of Hitler. My favorite such mission statement is in Ian Kershaw's two-part biography, Hitler: 1889–1936 Hubris and Hitler: 1936–1945 Nemesis (1998, 2000), laid out at length in the second volume:

In Greek mythology, Nemesis is the goddess of retribution, who exacts the punishment of the gods for the human folly of overweening arrogance, or hubris... History has no shortage of examples among the high and mighty, though "nemesis" tends to be a more political than moral judgement... Hitler's nemesis as retribution for unparalleled hubris would prove to be not just a personal retribution, but the nemesis of the Germany which had created him. His own country would be left in ruins—much of Europe with it—and divided.

Kershaw's hubris/nemesis theory—hammered over the reader's head repeatedly throughout more than 2,000 pages—is one way (although far from the only way) to understand Hitler: not as a monster, but as a human being who raised a terroristic police state in a country that was ripe for tyranny. More skillfully than most, Kershaw balances individual responsibility (Nazi Germany could not have come about without Hitler) with historical context (the political structures and social forces in place when Hitler seized power) in a way that other books, such as Hitler's Willing Executioners (1996), do not.

(3) Conversely, portraying Hitler as a monster (rather than a monstrous individual in a conflicted, and racist, society) diminishes him as a subject. When he wrote Rise and Fall, still (rightly) considered the most authoritative book on the subject, Shirer was little more than a decade removed from the events he was writing about. His source material was not only thousands of pages of documents from the confidential archives of the German government, captured at the end of the Third Reich in spring 1945, but personal experience (he worked in Germany as a radio correspondent for CBS from 1938 to 1941, writing three books: Berlin Diary [1941], The Nightmare Years [1984], and "This Is Berlin" [published posthumously in 1999]). Although Shirer states at the outset that he plans to be "severely objective" despite his "loathing" for Hitler's dictatorship, his palpable disgust for the people and events he's describing flattens his characterizations—for example, when he portrays Luftwaffe leader Hermann Goering as a clownish, obese buffoon; gay S.A. leader Ernst Rohm as a revolting sexual deviant; and party "philosopher" Alfred Rosenberg as "muddled," "shallow," and "confused." It's understandable that Shirer—a firsthand witness to the horrors of the Third Reich whose radio career in Berlin was ended by fascist censorship—would feel this way, but I prefer the further-removed accounts of John Toland (Adolf Hitler, 1976) and Kershaw to Shirer's exhaustive but still-seething overview.

(4) If you read Shirer, you'll have a relatively thorough education on Nazi Germany. However, if you want to go deeper, I would recommend Rise and Fall, Kershaw's two-part biography, and Richard J. Evans's now-three-part series, The Coming of the Third Reich (2003), The Third Reich in Power (2005), and The Third Reich at War (2008).

(5) There is something highly rewarding—even gratifying—about watching the bad guys get theirs. My favorite stories about the Nazi era take place in April 1945, when Berlin was surrounded in every direction and Nazis who hadn't left Berlin already realized they never would (Magda Goebbels forcing her children to take poison, Hitler's last look at the city he'd destroyed, loyal Nazis hastily gathering gasoline to burn Hitler's body along with that of Eva Braun). For the most thorough description published to date of the last moments of the Nazi regime, I recommend Antony Beevor's The Fall of Berlin 1945 (2002), a grisly, bloody, absolutely devastating book that includes one of the most detailed accounts yet of those final, desperate days.

(6) Constantly reading about horrors makes every part of your life a little horrible. For the first six months of my year of Hitler, I didn't relate the symptoms I was having—the grisly nightmares, the lousy moods, the sudden, random bouts of despair—to the fact that I had immersed myself voluntarily in one of the darkest periods in recorded human history. In fact, I think it only dawned on me that my Third Reich/Hitler obsession was skewing my outlook (and my relationships with other people, who got tired of hearing about this or that theory or version of events) when I started reading We Wish to Inform You That Tomorrow We Will Be Killed with Our Families, Philip Gourevitch's indispensable 1998 account of the Rwandan genocide, as "relief" from World War II Germany and the Holocaust. So now I really am taking a break. Albert Speer's Inside the Third Reich (1970), Hannah Arendt's Eichmann in Jerusalem (1963), and Ernst Hanfstaengl's Hitler: The Missing Years (1957) will have to gather dust on the shelf. I just picked up Barbara Walters's juicy autobiography, Audition (2008), and let me tell you—compared to Hitler, it's candy.

This story has been updated since its original publication.