PROLIFIC GARRY WILLS, on the wing in so many directions at once, is a hard man to draw a bead on. In the last year or so, while others dawdle over pages and paragraphs, he has published The Kennedy Imprisonment (impressive) and Explaining America (unpersuasive), all the while grinding out a syndicated newspaper column.

Now this collection of his longer journalistic pieces, representing some 15 years of work for Esquire, The New York Review of Books, and other journals, reminds us of his prowess as an essayist.

It is considerable, although a map of the progress of his opinions would be a bit confusing. Once one of William Buckley's gifted prot,eg,es at National Review, Wills then drifted leftward but now--see his stern judgments on the Democratic Party reform movement--seems to be settling back toward the center.

He is a learned as well as lively writer; and within the donnish robes of the classicist and Chesterton scholar there lurks also a holy terror who flashes his ex-seminarian's badge intimidatingly at those less well instructed in Catholic arcana. He tells us that he must "turn words over on paper . . . simply to make my mind work." But the result is often dazzling. Wills sometimes writes as if he were present at the creation of English--journalistic English, at least. Despite its thin autobiographical disguise, Lead Time is a standard collection, on varied subjects and themes.

Wills is at his best as an examiner of character. He is hostile--fortunately so, to my taste--to facile psychologizing. His mode is strenuous interviewing, tireless observation, shrewd reading, all culminating in humanistic judgment.

He is a prodigious collector of interesting information. Sometimes, as in his profile of Pope John Paul II, it turns out to be information that no one else bothered to dig up. Who else has troubled himself to discover the nuances of the pope's World War II record? (Karol Wojtyla was not, as sometimes reputed to be, a Polish resistance hero). Who else would deploy Robert Louis Stevenson against Governor Jerry Brown? Wills does a satisfying demolition job on Brown's intellectual pretensions--and, by the way, on his quasi-religious asceticism: "His preferred rite," says ex-Jesuit seminarian Wills of ex-Jesuit seminarian Brown, "would be all Ash Wednesday, with no Easter."

He is equally acute on recent presidents. Jimmy Carter, for instance: "For a bright and educated modern man . . . he shows an extraordinarily reined-in curiosity . . . quick and certain within a deliberately circumscribed territory." And Ronald Reagan: "The serene beneficiary of turmoil, the amateur foil of professionals, the sane relayer of craziness . . . His very flaws promote him . . . He floats above the quibbling because it never touches his self-esteem."

Wills reached the judgment on Carter after asking him whether, as a Bible reader, he had considered Bultmann on form criticism. (He had not; who was this Bultmann?) Nothwithstanding this deplorable lacuna, Wills seems to have been rather smitten with Carter in 1976. But a waspish later essay on Bert Lance shows that the enthusiasm soon subsided.

Perhaps the best of the pieces here are in the section called "Athletes." Wills, as much at home with sports and music as with politics, examines how several accomplished artists (Muhammad Ali in boxing, Raymond Berry in pro football, Beverly Sills and Shirley Verrett in opera) use their bodies as "instruments." The reporting is excellent, the texture for once untroubled by the pedantic jabs Wills is prone to.

All Wills's proficiency with information has a flaw-- his tendency to show-offy glibness. Writing of the pilgrimage of Memphis garbage workers to the King funeral, Wills takes a gratuitous dig at Nathan Bedford Forrest, the Conferderate general for whom one of Memphis's posh residential sections is named. Forrest, he says, "after the (Civil) war . . . took command of the Ku Klux Klan, which made him 'society.' " It is a trifling cheap shot. Does Wills know that Forrest hastened to call for the Klan's disbandment when President Grant asked him to--a gesture perhaps more revealing than the imputed snobbery?

Perhaps the best of the pieces here are in the section called "Athletes." Wills, as much at home with sports and music as with politics, examines how several accomplished artists (Muhammed Ali in boxing, Raymond Berry in pro football, Beverly Sills and Shirley Verett in opera) use their bodies as "instruments." The reporting is excellent, the texture for once untroubled by the pedantic jabs Wills is prone to.

Elsewhere, writing about Gerald Ford, Wills "fancies" that "the real explanation of Richard Nixon's pardon is that . . . Ford, totally of the House, Housey, just wanted to be friendly with everybody after the accident." Ford is a generous spirit; but less fanciful interpreters of the pardon believe, more plausibly, that he wanted the Nixon problem off the national agenda while he attempted to clean up the mess.

Wills takes such digs regularly. He is also capable of extravagant, if backhanded, generosity. Thus Nixon was "a fundamentally decent man until he took up politics"; and, in his view, the friends of Alger Hiss "were deceived to advance a cause, not to salvage a career."

When the cleverness is under control, which is most of the time, Wills's pieces sparkle and sting. He is almost always readable, and often more than readable. Lead Time is a far better book than his recent labored polemics on the political theories of the founding fathers. It is, for my money, clearly his best effort since Bare Ruined Choirs and Nixon Agonistes.