BAD BOOKS by good authors have a certain melancholy interest. When it's an exceptionally bad book by an exceptionally good author, the interest becomes intense. You want to figure out what went wrong.

Mickelsson's Ghosts tells the story of one year in the life of a 50-year-old red-haired professor of philosophy named Peter Mickelsson. It's is second one teaching at the State University of New York at Binghamton, where he came form a distinguished career at Brown, after a divorce and a nervous breakdown. He is the big shot of their philosophy department.

No one can say that it is not an eventful year. Here are some of the things that happen. Mickelsson suffers a full-scale investegation by the IRS. He buys a haunted house in the Pennsylvania mountains, and is haunted. He comes to a new understanding of Nietzsche and of Martin Luther. He goes to about 20 faculty parties. He murders a blind man in order to get money to pay a 17-year-old prostitute who claims to be pregnant with his child (she's certainly had ample opportunity) -to pay her not to have an abortion, but instead to bring a new little Mickelsson into the world. He masturbates frequently, sometimes meditating on the wives of his colleagues as he does so. He has dreams. He teaches a freshman class in Plato and Aristotle and a graduate course in medical ethics. He has an affair with a gorgeous -and brilliant -woman of 35 in the sociology department, and at the end of the book they are in the midst of a transcendental copulation (at a faculty party, on top of the coats). Later they will get married.

Done right, this could be a rich full account of the kind of complicated life many people really lead, and that art seldom acknowledges. Philosophers do mastubate (I presume), but Plato never mentions it, just as Hawthorne has nothing to say about Hester Prynne's modes of sexual entertainment when Dimmesdale is not around -which is all but a few nights of her life. Basil Ransom in Henry Janes' The Bostonians doubtless has dreams night after night, but James passes over them in silence. Meyer Wolfsheim in The Great Gatsby probably takes antacids reguarly, but Scott Fitzgerald does not go into this, as Gardner does with Mickelsson; he simplifies. Done right, Gardner's density of detail could be wonderful. But it's done -if not all wrong (he's too skillful a writer for that), at least mostly wrong.

The wrongest thing about this book is that the author is too infatuated with Peter Mickelsson. In the end, he thinks that anything Mickelsson does, says, or thinks is going to fascinate the reader, simply because it has happened. But it comes out merely the interest any narcissist feels for his won diary or his own face in the mirror, and the reader often couldn't care less.

Furthermore, this infatuation makes Gardner both indulgent and careless. He tells you that Mickelsson is a bad teacher (and from the three classes that are presented at appalling length, I heartily agree), but then he can't resist having female students get crushes on him, male ones revere and copy him, etc. It's obvious he really thinks Mickelsson is a super-teacher -bored, disgusted, and often cutting class, to be sure -but even in this disarray far above the common herd.

Or consider Jessica, the beautiful and brilliant sociologist (Harvard Ph.D. at 22). She's a fantasy figure, like some of Hemingway's women. Widowed a year now, she remains totally free and available for Mickelsson, whenever he chooses to beckon. At first this seemed improbable to me, considering her absolutely fantastic attractiveness of mind, body, and spirit. Eventually I realized that she is actually just Mickelsson-as-a-women, and of course she wouldn't bother with other men. Superwoman waits for Superman. One clue is that early on you learn that Mickelsson "had outpublished the pack of them" (in the Binghamton philsophy department), while a couple hundred pages late you learn that Jessica "had outpublished the pack of them" (in the Binghamton sociology department). And there are others: the god-like height of each, the fantastic sexual energy of each, and so on.

But the book has other faults beyond this monstrous indulgence. For one, it tries to pursue far too many themes. At one point I made a list of about 20. A running series of attackes on Mormons goes through the book. Another on Marxist sociologists. There are not one, not two, not three, but four phychics in the book, all different. There' a theme of redhaired characters (nothing is done with this). There are several varieties of pornography. Well-handled, too -even if in the end I didn't believe a man of 50 could get that many erections.

For another, Gardner simply gets careless. As in any narcissist fantasy, inconvenient details get forgotten. I have a list of inconsistencies as long as my list of themes.

Mostly they are trivial matters -Mickelsson seriously recommending Nietzsche to a student who (a) has already heard the great professor quote him constantly in class, and (b) is the student in all Binghamton who most reveres Mickelsson, and knows his life and tastes the way Boswell knew Johnson's. Or Mickelsson being presented in the first chapter as the moody Byronic hero, "a man who rarely went to parties" -and then something like a quarter of the book occurring at parties. Trifles. But these trifles add up, and they make the reality of the book blurry.

John Gardner being who he is, there are also brilliant scenes. But I have to say that much of the time I simply did not want to turn the pages. I did not want one more lecture on modern art or on Mormons. I did not want to learn what shape hors d'oeuvre Mickelsson chose from the tray at Dean Blickstein's party. I wanted all scenes but four or five of the best to be shorter than they were.

It is tempting to say that John Gardner needs a good editor. But it's not the case. What he needs is self-control.

The poet Roy Campbell once wrote scornfully on novelists who had technique without genius:

They use the snaffle and the curb, all

right;

But where's the bloody horse?

John Gardner has the horse -and it's a 16-hand stallion, at that. How I wish he would get himself a curb bit and good reins, stop trying to be Genghis Khan's whole army, and learn to ride in one direction.