IF I WERE TO CHOOSE a single word to describe the

literary essays of Howard Moss I would plump for "informed." That epithet may sound a bit dry, but consider first its possible associations--learned, reliable, gracefully authoritative, artistically shaped.

Moss' essays, half of which appeared in The New Yorker where he has been poetry editor since 1950, reveal a man who loves his subjects--not by accident are the best pieces memoirs of Auden, Elizabeth Bowen, and Jean Stafford. That affection Moss duly supports with precise thinking, telling example, and a prose that is lucid, musical and confident. Among men of letters perhaps only V.S. Pritchett writes a better plain style.

As a reviewer, Moss does several things well. A much admired poet himself, he brings a practitioner's understanding to the evaluation of poetry. Auden and Elizabeth Bishop recur throughout Whatever Is Moving as his touchstones, both masters of their craft from an early age, ever themselves. Auden, Moss astutely notes, is "our supreme journalist of the imagination"; of Bishop's work, he more quietly asserts, "There is a great deal to be said for scope, but more to be said, I think, for the absolutely achieved."

Not content with merely describing a book--"What pleasure is there in writing criticism that reveals what everyone can see for himself?"--Moss also knows how to use the review form: he slides from Cavafy's appealing blend of the historical and erotic into shrewd observations on why homosexuals chronicle urban life so well; he gives lilt to a close reading of Chekhov's The Three Sisters by interlacing suggestive musical analogies. And in both essays, he drops in sentences that might be aphorisms from La Rochefoucauld: "The truth is that what is interesting about love is how it doesn't work out."

In the more general essay, Moss proves equally good, as in the "The First Line," a fugue-like meditation on the importance of a poem's opening, of the weight of seeming inevitablity to such lines as "April is the cruellest month". "One would," he says, "no more think of revising a rock." Similarly, the concluding appreciation, "One Hundred Years of Proust," sharply defends Proust against charges of being frivolous and effete, then defines his true achievement concisely and beautifully.