Lionel Trilling (1905-1975), the regal American literary and social critic, was an ardent letter writer — he composed as many as 600 a year — but a slow-moving one. Corresponding with him was like playing squash with an opponent who pockets your serve, walks off the court and returns four months later to fire it back.

Nearly all the letters in “Life in Culture: Selected Letters of Lionel Trilling,” edited by Adam Kirsch, begin with apologies and small arias of explanation for delay. Most of these explanations have to do with course- and committee-work at Columbia University, where Trilling taught for most of his career. Sometimes the excuses were existential. My favorite appears in a 1951 letter, in which Trilling tells Norman Podhoretz that “nothing less than the totality of The Modern Situation, the whole of Democratic Culture, has kept me from writing to you.” Kids, do not try this excuse at home.

Trilling liked to hold off until there was, as he says in one letter, “a decisive occasion” for responding. (“Decisive Occasions” would have been a good alternative title for this well-edited volume.) He liked to let matters settle, to wait until the lava had cooled. His temperament was close to Olympian. It was demeaning, to borrow a line from the poet A. R. Ammons, to allow one’s Weltanschauung to be noticeably wobbled.

This settled quality makes Trilling’s letters a bit toplofty and dull. There’s no crackling sense of him pivoting in his Upper West Side war room, as there is in, say, the letters of his fellow midcentury critic Dwight Macdonald, who tended to sign off “More in anger than sorrow” or vice versa. Trilling’s letters read, in this selection, like well-appointed essays. You have to look hard to find the sort of human details (reports of meals, travels, vices, personages, vexations) that coax good books of letters to life.