Hurry up, please, it's time. Time, that is, to read E.M. Forster's "A Passage to India," the real thing, before David Lean's cinematic adaptation of it opens locally this coming weekend. The hunch here is that the Lean version will prove to be as much a masterpiece in its own fashion as the Forster original; but if you see the movie without having first read the novel, you'll deprive yourself of one of the great pleasures of modern literature.

This I say with the zeal of the new convert. "A Passage to India" was, until I took a busman's holiday during the month of December, one of too many important books that for one reason or another had escaped my attention. As a friend put it the other day, he'd so often heard it described by teacher after teacher as "the perfect novel" that over the years he developed a powerful resistance to it; for him, as for me, it had become one of those obstacles along the path to knowl- edge that one looks forward not to climbing but to having climbed.

Thus it occupied a prominent place in a stack of books I assembled last month with the intention of using the slowest month in the book reviewer's year to revisit, or visit for the first time, some of the major literary works of the past century. For the first time in three decades I slogged my way through the interminable military and philosophical digressions of "War and Peace" (I cannot imagine how I had weathered them as a 15-year-old) and the considerably more engrossing tribulations of "The Brothers Karamazov." Then it was on to "A Passage to India" -- and then it was that my carefully constructed schedule crashed off track.

In the life of a passionate reader there are occasional and utterly unexpected epiphanies: moments when one encounters a writer for the first time and discovers the dawning of a whole new world. These most often happen to teen-agers, for whom every day is (or should be) a process of discovery; for the adult, who is more likely to be jaded and less receptive to surprise, their occurrence is all the more to be treasured precisely because they are so rare.

Reading "A Passage to India," in any event, was just such an epiphany for me. In it I discovered not an austere "classic" but a book that is as alive and pertinent today as it was when first published in 1924. In its author I discovered a writer who possesses all the qualities I most admire: wit, civility, modesty and compassion, not to mention a prose style that puts just about every other novelist to shame. So instead of moving along to Anthony Trollope, I moved along to more Forster: All the other novels except "Maurice," the posthumously published "ho- mosexual novel" that is so widely disdained (for literary rather than sexual reasons) that I decided not to risk diminishing my admiration.

Not counting "Maurice" there are five novels in all (as well as two small story collections), of which "A Passage to India" is certainly the most ambitious and accomplished. One of the great literary mysteries of our time is that it is also the last. Though Forster lived nearly a half-century after its publication, he wrote no other novels, and no one knows why. His biographer, P.N. Furbank, offers three plausible explanations: that Forster was "of the type defined by Freud as 'those wrecked by success' "; that, "being a homosexual, he grew bored with writing about marriage and the relations of men and women"; and that after the triumph of "A Passage to India" he simply had no fictive terrain left to explore.

This last is the most persuasive, though it does little to ease one's frustration at being denied more fiction from Forster than we now have. But quite apart from "A Passage to India," what we have is in truth a great deal. "The Longest Journey" is a mixed bag: exceedingly funny in its depiction of life at a third-rate public school, but rather too sentimental in its obeisance to the good Pan, for whom Forster had a bit too much aaffection. For a first novel, "Where Angels Fear to Tread" is a considerable achievement. But "Howards End" and "A Room With a View" are smaller than "A Passage to India" only in the sense that their canvases are smaller; as works of art, and as illustrations of Forster's style and themes, they are exemplary.

The best criticism of Forster I've thus far read was written by Lionel Trilling, in a little volume devoted to his work that was published in 1943 as part of the "Makers of Modern Literature" series. He says: "Forster is not only comic, he is often playful. He is sometimes irritating in his re- fusal to be great. Greatness in literature, even in comedy, seems to have some affinity with great- ness in government and war, sug- gesting power, a certain sternness, a touch of the imperial and im- perious. But Forster, who in cer- tain moods might say with Swift, 'I have hated all nations, professions and communities, and all my love is for individuals,' fears power and suspects formality as the sign of power. 'Distrust every enterprise that requires new clothes' is the motto one of his characters inscribes over his new wardrobe."

This is in Trilling's judgment a shortcoming: "New thoughts sometimes need new clothes and the seriousness of Forster's intellectual enterprise is too often reduced by the unbuttoned manner he affects." But it is a manner of great appeal to the reader in an age of hyperbole, self-importance and solemnity. As Trilling understood, Forster knew the difference between seriousness and solemnity, and his comedy is more serious in nature than even Trilling seems to have grasped.

As much as anything else, "A Passage to India" is a great comic novel. There is a deep under- current of sadness to its depiction of the irresolvable clash between eastern and western cultures, but Forster gives humanity to that clash by making it comic; every subsequent writer who has treated the subject from Graham Greene to V.S. Naipaul to Paul Theroux, stands in his debt. And only a wise and comic man could write, as Forster does: "Life never gives us wha we want at the moment we consider appropriate. Adventures do occur, but no punctually."

Of such wisdom and comedy is "A Passage to India" constructed. Its greatness is not cosmic but intimate, not daunting but inviting. To contemplate its new existence in the hands of the masterly David Lean is a great pleasure, but nothing he does to it will alter the brilliance of the novel. Like India itself,"A Passage to India" is part of the modern landscape.