Some of my most enjoyable reading has come from authors who draw conclusions I find absurd or irrelevant but who are artful, hard-working and aggressive in the drawing. It is bad business on any occasion to read too many writers with whom you agree, but it's a genuine treat to discover an opposing voice who writes with passion and instinct.

The first paragraph of Monsignor Kelly's examination of American Catholicism was enough to persuade me that I would be agreeing with little of what was to follow: "A guerrilla-type warfare is going on inside the Church and its outcome is clearly doubtful. The Pope and the Roman Curia are fending off with mixed success the attacks of their theologians who, in the name of scholarship, demand more radical accommodation with Protestant and secular thought. The issues at stake are the correctness of Catholic doctrine and the survival of the Catholic Church as a significant influence in the life of her own communicants."

I have no sense that a war is going on now within the church. If anything the war is over, the one in which church leaders took Catholicism into the bunkers and began imagining that the enemies of God were everywhere. We are beyond that now, at least to the point that Catholics no longer see themselves as helmeted outsiders dodging the bullets of a hostile secular state.

Msgr. Kelly traces what he sees as today's "fights about God, Christ, redemption, revelation, Church, about the final things in life" to the days following the Second Vatican Council. He cites a noted scripture scholar who likened some bishops to "a drunken father" whom "we try to hide when company comes, and we worry about what half-wit blunders he will make next."

The council, putting an end to "Catholic serenity" created "organized factionalism." Msgr. Kelly, an able historian, cites Arianism, Manicheism, Pelaginanism and Calvinism as earlier deviations from church teaching. But the post-Vatican II era was different because the changers and fixers didn't jump ship to become celebrities.

They grabbed for the rudder and became celebrities.

This is what angers Msgr. Kelly the most. Deviations are bad enough, but when these "religious crimes" are tolerated in high places then there is "real evil." The hierarchical structure falls apart. If those who give the orders are weak in their authority, those meant to take them become strong in their disobedience. "Defiance," he writes, "within the upper echelons of espiscopal bureaus, theological societies, Catholic universities, and religious orders is the contagious canker sore on the Church body."

I confess that I would probably be more receptive to the monsignor's arguments if I had more at stake in the future of the church. But as with most laymen, the obligations, pleasures and opportunities of the daily things -- family, work, the daily 10-mile run -- mean that concerns about Holy Mother church are far down on my worry list. It's enough, sometimes, merely to make an examination of conscience if only to be sure that your conscience is still there.

I admire priests like Msgr. Kelly because they were holding true before the council came along, and now they are still erect, long after the dissenters and people like me have gone on to other causes. But some of these durables may be acting out of bullheadedness for all I can tell and I don't know that cranky stubborness is one of the Christian virtues.

If it is, and if Msg. Kelly is guilty of it, then he more than does his penance in this book by his sharp commentary on Rev. Andrew Greeley. He is not taken with Greeley's posturing and self-promotion. Until Msgr. Kelly wrote of it, I hadn't realized how many sociologists -- scholars like Paul Hanly Furfey of Catholic University -- have dismal regard for Greeley.

It hurts to admit it, but I enjoyed nearly every page of Msgr. Kelly's book. His intelligence is forceful and he is able to be angry without being mean. He loves his church and thrives on its teachings, ancient and modern.

He believes that at some point "the bishops and the Pope will have to lay out the rules for the new Church once and for all and make them distinguishing marks of a bona fide Catholicism . . . Not only will bishops be required to say clearly and with authority where the renewed Church is going, but they will also need to delineate what they will not accept. They will also have to appear to mean what they say. They will have to swim against the strong currents in the cultural tide of the United States."

As a fine swimmer himself -- a marathon swimmer, it would seem -- Msgr. Kelly is the director of the Institute for Advanced Studies in Catholic Doctrine at St. John's University, New York. The school is lucky to have him and the public is fortunate to have his book. With the Holy Father here in our presence, it is a good moment to learn what one of his most loyal followers is thinking.