Being a historian is a bit of a slog: years in graduate school, more years in dusty libraries and archives, and even more years teaching students who sometimes don’t seem interested in learning what you have to teach. But the job does have its pleasures, and one of the greatest–and surely the guiltiest–is watching people screw history up. Not a day goes by when we don’t see someone get it wrong, dead wrong, or so wrong that it’s not even wrong. To us, history is firmly anchored in authenticated sources that have been subjected to intense scrutiny and debate by people who know what they are talking about. To most other folks (though surely none of the people reading these words), history is something a dimly remembered teacher taught you, something you saw on the “History Channel,” or something someone told you once. This kind of history is not anchored in anything other than popular ideas and attitudes, which themselves are constantly changing. In this light, it’s not particularly surprising that when most people talk about history, they don’t get things quite right. When people make historical mistakes, we historians earnestly knit our brows and solemnly bemoan the deficit of historical knowledge. Privately we sometimes chuckle. I’ve done this myself, and I have to tell you I feel bad about it.

I can only imagine, then, that Christopher Krebs had an absolute blast writing A Most Dangerous Book: Tacitus’s Germania from the Roman Empire to the Third Reich (Norton, 2011), for it is an epic tale of getting it wrong, history-wise. Beginning about half a millennium ago, people began to say all kinds of wrongheaded things about Tacitus’s thin volume: that Tacitus was writing about “Germans” (he wasn’t); that he knew a lot about “Germans” (he didn’t); that he uniformly praised “Germans” (nope); that the traits he ascribes to “Germans” can be found among modern German-speakers (wrong again).

Were it not for the fact that these “interpretations” emboldened evil people (especially the Nazis) to do evil things (too numerous to recount), this exercise in bad history would be funny. But, as Krebs points out, it’s really not very funny at all. It’s a reminder that we professional historians have a duty to make sure we get what we say about the past straight, or else. Christopher Krebs is clearly fulfilling his duty in this important, readable, and very witty book. It deserves a wide audience. That means you.

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