“Oh God, this is a calamity for American literature,” Kurt Vonnegut said on learning of Joseph Heller’s death in 1999. John Updike was less alarmed: Heller “wasn’t top of the chart” as a writer, he reflected, though he was “a sweet man” and his first novel, “Catch-22” was “important.” Note the Updikean judiciousness of “important”: he didn’t say he liked the book, but it was a great cultural bellwether as novels go, and it has endured. Despite mixed reviews on publication in 1961, “Catch-22” was soon adopted by college students who recognized a kindred spirit in Yossarian, the bombardier who rebels against a materialistic bureaucracy hellbent on killing him. “Better Yossarian than Rotarian” became a popular slogan, all the more so with the timely (for the novel’s sake) military escalation in Vietnam, which became the “real” subject of “Catch-22” and partly accounts for its sales of more than 10 million copies to date. It’s hard to argue with that kind of importance.