The first point to be clarified is a grammatical one. The last word in the title of Andrew Greeley's first novel is a noun, not a verb, and the second word is not the title of an ecclesiastical dignitary but an adjective meaning "primary" of "fundamental."

This explanation is necessary, because one might easily become confused. There is a central character in the book who becomes a cardinal and who spends quite a bit of his time sinning. Father Greeley (for he is a priest and plans to remain one) asures his readers that what he means by "cardinal sins" is the traditional list of "deadly" sins: pride, covetousness, lust, anger, gluttony, envy and sloth -- prime material for novels, and all abundant in this one.

Greeley insists that "the cardinal sins have nothing to do, of course, with the members of the Sacred College, who, as we all know, commit hardly any sins." He strains credulity even more, two pages later, when he mentions that his book "is story, not history or biography or (perhaps sadly) autobiography. It is nonetheless true." If it is, in fact, a work of pure imagination, it draws heavily on reality, so much so that Greeley is forced to use asterisks with his "Cast of Ecclesiastical Characters" to show which are real and which are invented. Among the real ones is Cardinal Korol Wojtyla, archbishop of Krakow. But he is not the cardinal who does the sinning in the book; that is one of the asterisked characters, Patrick Henry Donahue, seventh archbishop of Chicago, who crowns a rather strange career (marred by financial and sexual misdealings) by helping Wojtyla become Pope John Paul II.

The interesting thing about the book, and the central point in Greeley's implied criticism of the Catholic hierarchy, is that the human weaknesses of Patrick Donahue are among his most appealing qualities, while the things that advance his career are what make him a sort of monster. Greeley (speaking through a character who clearly represents him) indicts a large segment of the American hierarchy in a thumbnail portrait of the "antisocial personality" of one fictional prelate: "Cannot establish relationships of trust with other persons; does not care about others' feelings, doesn't even know that they have them; cannot distinguish between truth and falsehood; does not keep his promises; has no principles; can be the most charming and personable man imaginable, when he wants to be." Men like this are, by and large, the kind of people who rule the Catholic Church and participate in papal elections, Greeley indicates. And in the story of Patrick Henry Donahue, he tells how they get that way and how they reach that position.

If there is anything Andrew Greeley knows about, we may assume, it is how people become popes. He has written a nonfiction book about it, "The Making of the Popes," which was probably his most widely discussed work until now. But "The Cardinal Sins" will certainly replace "The Making of the Popes" in that distinction and may get him on even more television talk shows. If the abundant sex, political skulduggery and financial shenanigans in the book don't accomplish this, its $75,000 advertising budget will.

Curiously, considering the author's background, the election of Pope John Paul II is the point where his novel breaks down. It seems to be going along quite well until near the end, and suddenly he shifts from a compassionately human story of love and ambition, struggles against arbitrary authority and outmoded rules, and throws in some unbelievable (because unskilled) cloak-and-dagger episodes, centered on the efforts of a group of conservative terrorists and blackmailers to influence the papal election. The priest-narrator of the book, Kevin Brennan, steps out of his role as a scholar and shepherd of souls, briefly becomes a sort of reverend James Bond, and shows that Andrew Greeley's abilities as a novelist are not unlimited.

Until then, the performance is quite impressive -- more so, for example, than that of another priest, Eugene Kennedy, in the recent novel "Father's Day." Greeley traces the lives of Brennan and Donahue, from 1948, when they are still in high school, until the present, when Donahue has become a cardinal and a member of the ecclesiastical bureaucracy in Rome, while Brennan has become a social scientist affiliated with the University of Chicago -- still a priest but no longer on the chancery office's mailing list. This is a fair description of Greeley's own situation, although, as he insists, there are other ways in which he does not resemble the point-of-view character in his book.

Greeley's academic discipline is sociology, and in the background of his novel he presents a thorough picture of what he has seen happening to the Catholic Church in the last generation. Outside of the private lives of his characters, the central event is the Second Vatican Council and the ferment it stirred among Catholics. Some of Greeley's best pages are those in which he shows how rather abstract questions of church structure and discipline affect the lives of ordinary Catholics -- particularly the two women, Ellen and Maureen, who are almost as important to the story as Patrick and Kevin. Greeley's descriptions of women and sex as better than one might expect from a man in his position. So is the novel as a whole, until it succumbs to the Ian Fleming heresy near the end.