NECESSARY ERRORS, by Caleb Crain. Penguin, 472 pp., $16 paper.

"Prague doesn't let go," Franz Kafka once wrote of his hometown. "This little mother has claws."

advertisement | advertise on newsday

That line neatly summarizes the tension in Caleb Crain's elegant and intellectually robust debut novel, "Necessary Errors." Its hero, Jacob, is a 20-something American navigating familiar 20-something crises: love versus lust, accomplishment versus slackerdom. Tales of such post-collegiate expats are usually thin studies in privileged narcissism. But Crain complicates the story, using the Prague setting to explore the ways post-Cold War Czechoslovakia both embraces and wounds his characters.

Jacob pays the rent teaching English, a profitable enterprise in 1990 as the newly liberated nation craves Westernization but hasn't yet raised prices in ways befitting a market economy. Early on, Jacob is only dimly aware of the capitalist striving that surrounds him. But when the man he falls for shortly after his arrival turns out to be a prostitute, Jacob gets wise to both love and economics: "It was after all a country full of people who expected to become hateful as they learned to do things for money," Crain writes.

Passivity is an essential part of the expat experience: Jacob, like many wide-eyed foreigners, isn't doing things so much as allowing things to happen to him. That's hard to energize in fiction, but "Necessary Errors" thrives on Crain's depth of understanding of the economic dynamic, and on his close study of social and romantic entanglements. The novel can be slow going at times, not because Crain is a plodding writer but because he's a patient one, calibrating the story's pace to the rhythm of Jacob's life. (When he pays a visit to go-go Berlin early on, the story noticeably quickens.)

"Necessary Errors" is thickened with a sizable cast of fellow expats whose experiences parallel Jacob's: Romances bloom and wilt, while financial opportunities alter jobs and loyalties. That gives the novel a spirit of camaraderie, as well as some lovely set pieces throughout the city, from the rivers and castles to bars and embassies. These young men and women are living in a bubble -- the first Gulf War barely registers on Jacob's consciousness -- and Crain potently captures the utopian mood. One of Jacob's lovers takes to him like "a duck into a pond -- dunked his head vigorously in, swam about happily, briskly shook his feathers clean afterward."

Yet Crain also makes clear it can't last, which gives this calm novel the necessary drive. Like Prague itself, Jacob will have to remake himself eventually, and Crain makes that need feel essential and bittersweet. "It was a mistake to think that in the new world they would be able to care in the old way," he writes. "In the new world you had to find something of value and learn not to care for it. You had to learn how to sell it."