GRAHAM GREENE has always taken great pains to defend himself, with a recusant air, from assumptions that he is a Catholic novelist. He did so in a preface to his brilliant The Comedians, and in his dark autobiographies, and in a recent conversation with Anthony Burgess in Saturday Review. He is a novelist in whose books there are Catholics, Greene always tells us, but he is not a Catholic novelist. He is wrong, of course. He is a Catholic novelist, and a wonderful one. He enlightens and elevates us all. The Nobel Prize committee doubtless rejected Vladimir Nabokov because he was politically conservative and, though Russian-born, lived in neutral Switzerland. Greene, very English, nevertheless lives in neutral-to-right-wing Provence and, like Nabokov, must strike the Nobel Judges as insufficiently political. I hope that they will examine his courageous insistence upon religious doubt, specifically Catholic doubt, and treat his faith as his nation. They should award him the Nobel Prize for Literature. It is time.

One opens Monsignor Quixote (to quote Greene on another writer) "with all the excitement that comes from complete confidence in the author." The confidence is rewarded: this is a witty, often funny, and very moving novel. It is not made gray by the dourness of some lesser of his novels (The End of the Affair, A Burnt-Out Case); this one is Greene with a vigorousness of storytelling pleasure, and with an author's excitement over right characterization. He is at his best in this novel, and he knows it. I could feel him feeling so, probably against his will, as he wrote. That knowledge communicates itself to the reader, page by page and chapter by chapter. And by the time Father Quixote was blowing up condoms like balloons in the bordello to which his latter-day Sancho had taken him, I was laughing out loud.

Quixote of La Mancha, an aging and comfortable parish priest, knows that he is descended from Don Quixote. While his bishop, who detests the unorthodoxy and zest in him, insists that a man cannot be descended from a character in fiction, the father quietly refers to Cervantes as "the biographer" of his ancestor. His Sancho Panza, the recently defeated Communist mayor of El Toboso, is named Zancas, "which was the surname of the original Sanchd Panza in Cervantes' truthful history." Quixote of course calls his moribund beloved Seat car "my Rocinante," after the first Quixote's horse. And that is the set of assumptions, offered from the start, with which this sweet novel begins. With two important exceptions, it is told, though in the third person, with the tone, and frequently the words, of Quixote's thinking. A peasant who is a priest and who is (nearly by accident) elevated to the rank of monsignor, Father Quixote thinks about his faith. His voice is the novel's, and Greene is never patronizing -- one hears the book as one hears the voice of a simple, decent, and thoughtful man.

When he is made monsignor, the father takes a leave and embarks with Sancho on a wandering pilgrimage through contemporary Spain, toward and away from his doubts. The first, effortless, chapter comences occasions for talk and more talk -- about Sancho's forlorn Marxism and Quixote's earnest Catholicism -- and provides a frame for tales and picaresque adventures, as well as lovingly wrought bibulousness. Never has wine been so well-appreciated in recent fiction. As the original Quixote loved outdated books of chivalry, so Sancho loves a Marxism that Communism has left behind, while our Quixote's favored books "are of chivalry too. Saint John of the Cross, Saint Teresa, Saint Francis de Sales." These two lovers of failed or neglected books of love drink and discuss their way across the crisscrossing paths of cruel Guardia and disapproving Church. They offer us important small decisions: that "Religion is the Valium of the poor"; that a white Roman collar may look "like a handkerchief signaling distress"; that the man who pos sesses complete belief lacks "the dignity of despair"; their speculations on birth control as related to moral theology are worthy of Hamlet's nurse and are worth the price of admission.

The analogy to Don Quixote, while used to propel the adventurers in our minds, is not that heavily leaned upon by Greene. And it does not merely enchant. It serves to remind us that fact and fiction are not always easy to separate: says a Trappist monk, who offers refuge to our heros, "Fact or fiction -- in the end you can't distinguish between them -- you just have to choose." Faith could be such a fictional process, Greene tells us; God could be its product. He writes, Greene reminds us, not about ease in faith, but about the pain of doubt -- intelligent religion, not mere miming of prayers.

Thus, the complaisant Quixote, who can say he wants others to believe because "I want them to be happy," reasons that "the believer will fight another believer over a shade of difference; the doubter fights only with himself." He reveals himself more and more, as the novel progresses, to be the doubter of whom he speaks. It becomes clear that while Quixote's love of God never diminishes, it is also true that "when I speak of belief, I become aware always of a shadow, the shadow of disbelief haunting my belief." In a stunning scene that is at once hilarious and saddening, Quixote hears the confession of an undertaker, who has stolen the brass handles from a dead priest's coffin, while the father sits, hand before his eyes, on the seat of a toilet in the compartment of a men's room in a bar: "He thought, 'I didn't say the right words. Why do I never find the right words? The man needed help and I recited a formula. God forgive me.'"

God might, but the church and state will not. Quixote is kidnapped by the church whose efficacy he doubts and whose mandarins he embarrasses. (The scene in which Sancho looks for him, and meets English-speaking tourists, is very funny and touching. The state is after Quixote and Sancho too, and we have been the Guardia, in deftly noted moments, more and more clearly menacing them. We feel actual threat accumulating, and when the idle journey becomes headlong flight, it feels like suitable action because Greene has made us feel that Quixote is born to be hunted. And he has made us feel that such a good man -- "O God, make me human, let me feel temptation. Save me from my indifference" -- is bound to be brought down by such a world as ours.

Unlike the father, Greene has felt temptation. He is human. But the women in this novel -- as if by now Greene, turned priest, were himself renouncing them -- are either literary (Don Quixote's Dulcinea), sainted (Th,erMese), or splendid incidental peasants (the father's housekeeper Teresa, who serves up horsemeat steaks as aged beef). Strong women of flesh and blood are absent, and it strikes me that Greene is comfortable with the absence. In his last novel, Dr. Fischer of Geneva, Anna-Louise, the narrator's wife, died early in the book; her hours of life on the page were rather unconvincing anyway. In the novel before that, The Human Factor, Maurice surrenders everything for Sarah and then must leave her behind. And in Monsignor Quixote, the central woman, not dead or deserted of necessity, is simply never present: she lives in the word of the church and the minds of believers as a saint. If Greene's personae are gradually stripping the life of flesh from themselves, his genius is not -- this novel has absolutely as much about the body of the world as it needs, and its lean and simple language offers us an amplitude.

A final triumph I must note is that of plot. A pilgrimage away from faith, toward faithful doubt and true humanity, becomes a flight from literature, a springing-loose of story from its source, and a victory of fictional character, Father Quixote cries out to Sancho, as the story tenses itself for its penultimate adventures, "Why are you always saddling me with my ancestor?. . . Those Guardia were Guardia, not windmills. I am Father Quixote, and not Don Quixote. I tell you, I exist. My adventures are my own adventures, not his. I go my way -- my way -- not his. I have free will."

The novelist, a doubting Catholic, declares his art to be free. And the novel, of course, from here on, is about a contest between Quixote and his fate. What occurs, Greene reminds us, is about a unique soul on the earth. Greene works hard -- as in his Public statements about his fiction -- to remind us that he is not writing propaganda for a church, or a literary source. He is concerned with how, in such darkness, the search for honest belief takes place. He makes his character work because of the story the father descends from. He then teaches us about writing as an art and story as its servant by making Quixote master of the story in which he began.

The end of the novel must remain between you and Graham Greene. You needn't bother to reread Cervantes' Don Quixote before you read this novel. But do read this novel. See if, at the end, as I was, you aren't amazed by how effortlessly Greene makes the obvious into something new, and the unlikeliest event into a real and plausible occasion. See, too, how he allows the word "love" to remain an honorable and useful one.

And those "balloons" in that bordello? The good father reads himself to sleep with the "prophet Marx," and he sleeps the whole night through. He is wrapped in darkness and wakened to light by the master, whom you ought to see at work and, most happily for us, very much at play. I don't know when he's been better. He is Rembrandt, with laughter.