IT WAS ONLY a matter of time. Sooner or later some bright entrepreneur had to realize that no other bright entrepreneur had yet written a serious book about Woody Allen. So long an omission was surprising but, in a strange way, appropriate; for one of the most tantalizing aspects of Woody Allen's much-touted talent has always been its uncertainty. Even after Annie Hall swept the Oscars, there were those who argued that Allen's brilliance denatured outside the narrow confines of Manhattan, and that the jokes and insights New York fans loved would not only fall flat but offend when transpose to a different environment. You never knew, either, whether the latest Allen film would be hailed or condemned as tripe after its initial upward climb. Not only did no one know what Allen would do next; no one was under any obligation to admire it.

Into the vacuum rushes film critic Diane Jacobs. "Only his analyst," burbles the book jacket, "could possibly know Woody Allen as well as Diane Jacobs." Jacobs does, in fact, take something of the analyst's approach: dutifully "listening" to, or in this case recounting, all the content of each of Allen's works, then examining it for patterns. She succeeds in detecting a few basic clues. The later movies are subtler than the early ones, for example, and Allen the artist separates himself more and more from Allen the persons. Oh, and there are some continuing themes: the contrast of the New York Jew-schlemiel personality with various exotic locates, say, and the difficulties of love in the modern world. But in order to deduce fro.. these indications anything illuminating or even interesting about Allen, maybe Jacobs could use a degree or two in psychology.

But We Need the Eggs may nab some buyers through its more-than-explicit promise to tell a lot of Woody Allen jokes, apparently all the ones Jacobs can remember. The hint in the title--which refers to the curtain line of Allen's best-received work, Annie Hall--is amplified on the back cover, where the paragraph containing the line appears in toto. It is also to be found on page 114, again in full, and at numerous other points in the text. If the reader prefers excerpts from Love and Death, or Bananas, or the early nightclub routines, or just pictures with explanations, they're all there as well, sprinkled liberally through the text.

There's nothing wrong, of course, with quoting good material--provided that it's quotable to begin with, and provided that you have a reason for quoting it. But Jacobs' chief reason for quoting Allen, other than to remind us and herself how great he is, seems to be convenience. Rather than describe articulately what sets one "period" or theme in the work off from another. Jacob tends to rely on a shorthand composed of repeated, encapsulated jokes. "Needing the eggs" is her analytic code for a type of humor she never defines, but which can be deduced to be the sober, questing, wistful quality in Allen that sends him harking after illusions. Likewise, the Take the Money and Run gag in which inept crook Virgil Stark well whittles a soap gun in jail, only to have it dissolve in the rain, becomes the officiated symbol of Allen's early humor, heavily based on such lively incongruities. To suggest a more subtle gagging which marked Allen's work from the earliest, there is The Moose (1965), a weird parable of hunting and anti-Semitism which Jacobs humorlessly and painstakingly traces.

SUCH DISSECTION makes one painfully aware not just of Jacob's essential un funny-ness as a commentator--she takes Woody with too much desperate seriousness to get any further than a string of "this is hysterical" --but also the delicacy of the task she has taken on. If writing about Woody seemed like a glowing, as-yet-un-snatched opportunity, the flip side is that a talent so multifaceted and subtle as his cannot be helpfully reduced to a series of art-vs.-life and success-vs.-integrity conflicts, or even to a run-of-the-mill Freudian manifestation. Quoting the opening passage of Love and Death("...all men go eventually, but I go at six o'clock tomorrow morning. I was supposed to go at five o'clock, but I have a smart lawyer..."). Jacobs notes that the film "opens in the concept/reality collision spirit of Getting Even." What she omits is why, or how, any of these gags are so effective--the obvious if thorny question in evaluating any humorist.

The "magic" of Woody Allen is at once an appropriate title and an indication of the task implicit in the subject. Those who want a methodical compilation of transcribed Allen jokes may as well turn to Getting Even or Without Feathers; that way, at least, they'll be spared the anxious author's attempts to supply context, justification and an inexorable order of development. Running as far toward the present as Stardust Memories, the book obviously cannot address Allen's latest, but the flaw is less than it might be, for no great effort of imagination is needed to deduce what Jacobs would say about it: It's funny, it draws on the difference between reality and dreams, it's set in the turn of the century, and it's very, very funny.

Better to wait through the next three movies, or six, or 10, and see whether the "magic" lasts in retrospect. If it runs deep enough to endure, then it is not to be pinned down now.