Alas, what he found among the city dwellers was different but still unnerving: an overbearing affection for the Jews.

Image Yascha Mounk

Most Germans, Mr. Mounk writes, “were so keen to prove to me that they weren’t anti-Semitic that they treated me with the kind of nervous niceness usually reserved for the mentally handicapped or the terminally ill.” What’s more, “The effect of their pity and their virtue was to leave both of us with the sense that I couldn’t possibly have anything in common with them.”

This philo-Semitism provides some sublimely ridiculous material. Caught insulting Woody Allen, his friend Franz backpedals for Mr. Mounk’s benefit, pathetically praising Mr. Allen’s “Jew humor” and extolling the film “Deconstructing Harry.”

Another acquaintance, Markus, surprises Mr. Mounk with a “Chag sameach!” (“Happy holiday!” in Hebrew). When Mr. Mounk expresses surprise, Markus explains that, when he was 13, he converted to Judaism after watching a documentary about the Holocaust. Later, however, he drifted away from the faith.

“Because you never believed in God?” Mr. Mounk asks.

“No, because I still feel guilty.”

Mr. Mounk skillfully puts Germans and Jews on his analyst’s couch. He notes that before the post-unification immigrant wave of the 1990s, there were fewer than 30,000 Jews in West Germany, a nation of 60 million.

“Each Jew had to be shared out among 2,000 Gentiles,” he writes. “From the very start, the German crush on Jews lacked for a real-life object.” And so, “On the whole, the love affair between Germans and Jews remained unconsummated, leaving all parties with a keen feeling of frustration.”

I could have done without Mr. Mounk’s theory about the effects of postwar shame on Chancellor Angela Merkel’s management of the euro-zone debt crisis — one of the tangents that reads as if his grad student superego spilled onto the page. On the other hand, his dissection of post-1968 German leftism, which bizarrely twisted anti-fascism into a sinister species of anti-Semitism, is cogent and haunting.