In “Lucky Alan,” fortunately, Lethem’s considerable strengths are on display, not just his language. “The King of Sentences” is a comic, cautionary story about the danger of being too precious, too arcane and too much of a fan. The narrator and his girlfriend, Clea, are a young, ridiculously literary couple, so enthralled by a well-sculpted sentence that the right one, uttered at the right time (“I can hardly bear your heel at my nape without roaring,” is an example), has the power to give Clea an instant orgasm. They work in bookstores, lowly clerks perhaps, but “custodians of a treasury of sentences” whose worth not a single one of their customers can appreciate or understand. They sneer, they revel, a cult of two.

Both, of course, are at work on novels of their own. Clea’s is called “Those Young Rangers Thought Love Was a Scandal Like a Bald White Head,” while his is “I Heard the Laughter of the Sidemen From Behind Their Instruments.” These aren’t so different from Lethem’s early titles, “Gun, With Occasional Music” and “As She Climbed Across the Table,” and we sense he is satirizing his own youthful enthusiasms for comic books, rock bands, unknown writers and showstopping language. The tone of the story is dead on.

The object of the couple’s worship is an obscure, older writer who lives in a Westchester suburb where, “beavering away,” he produces novels that were once published as mass paperbacks but whose sales figures by now are “likely descending to rungs occupied by poets.” In a state of deranged enchantment, the couple take the commuter train to surrender themselves to their idol, whom they have christened the King of Sentences. A local cop, present to make sure that their devotion doesn’t involve any sort of illegal menace, wonders with sage common sense if they’ve ever considered the content of the King’s books, not just the sentences. “Sentences are content,” Clea shoots back, and the conversation shuts down.

The King of Sentences, diminished, aged, in need of an inflatable doughnut to ameliorate anal discomfort, deigns to meet his fans. He isn’t happy to see them and, after trying unsuccessfully to send them on their way, exacts a gleefully vicious revenge.

Lethem, of course, is himself a king of sentences. In the title story, the protagonist is described as “a skater up his own river, a frozen ribbon the rest of us might have glimpsed through trees, from within a rink where we circled to tinny music.” This is just the sort of passage that would have made Clea swoon. But the content is equally satisfying. The story begins as a well-observed portrait of an elegant Manhattan bohemian of a certain age, then takes a more serious turn when the bohemian realizes too late that a neighbor has interpreted his teasing, solicitous affection as an insult. He is mortified to see that, for all his friendliness and good will, he has been treating his neighborhood acquaintances “as figures in a shadow play.” Unexpectedly, the story becomes a study of unrequited platonic love.