Justice delayed is justice denied, so justice demands that someone say this: It is not true tha young adults read nothing but T-shirts and books of cartoons. You must look all the way down to fourth place on the current list of campus best-sellers to find a cartoon book, and all the way to seventh place to find one about Garfield the cat.

The best seller deserves to be. It is Garrison Keillor's ''Lake Wobegon Days.'' And young adults even have a kind of cult book. It is Jay McInerney's novel, ''Bright Lights, Big City.''

It has something like the cachet ''Catcher in the Rye'' had in the golden age of college youth (meaning when I was in college). Indeed, a critic says ''Bright Lights'' is ''the 'Catcher in the Rye' of the MBA set.'' From the royalties, McInerney bought a BMW, naturally.

He has perfect pitch for the inner music of upscale young professionals networking on the fast track. His novel is the Michelob beer commerical re-invented as literature.

It chronicles one picaresque week in the life of a 1980s Holden Caulfield who is failing life as a fact-checker at a magazine as full of itself as The New Yorker. The novel's prefatory quotation is from ''The Sun Also Rises'':

''How did you go bankrupt?'' Bill asked.

''Two ways,'' Mike said. ''Gradually and then suddenly.''

The novel appeals to people mightily concerned about money, consumption and other sources of derivative identity. It suggests the state of mind (well, state of something) that has been called transcendental acquisition, spelled R-O-L-E-X. Something bad is ''too New Jersey for words.'' A grating voice sounds like ''the New Jersey state anthem.'' Tacky girls have ''an outer-borough look.'' What is good? Bloomingdale's, and a ''J. Press torso,'' and Twining's breakfast tea. And, always, croissants.

The protagonist is a downwardly mobile young man with a bad habit of ''hoovering'' cocaine and a tedious habit of wondering who he is. The novel begins: ''You are not the kind of guy who would be at a place like this at this time of morning.'' What other kind of guy isn't he? When in a disreputable night club: ''Your presence here is only . . . reminding yourself of what you aren't.'' Yet again: ''You see yourself as the kind of guy who appreciates a quiet night at home with a good book. A little Mozart on the speakers . . . '' ''You see yourself as the kind of guy who wakes up early Sunday morning and steps out to cop the Times and croissants. Who might take a cue from the Arts and Leisure section . . . The kind of guy who. . . . ''

Style and substance merge in the use of the second-person pronoun, the tone of voice of the self-absorbed. It is the voice of those Michelob commercials swarming with baby-boomers merrily gentrifying brownstones: ''You have a style in your life. . . . You're on the way to the top. . . . You've always known just who you are.'' McInerney's protagonist hasn't a clue who he is.

In McInerney's second novel, ''Ransome,'' the protagonist of that name is a Beverly Hills boy disgusted with dad, who is -- yuck! -- in television. Ransome goes to earth in Japan and converts (it is a demi-semi-religion for him) to karate, the practice of which ''conveyed an extraordinary sense of self-possession.'' Here we go again, more ''selfs'' being shopped for and possessed.

In a sense, McInerney is traditional to the point of being hidebound. Nothing is more traditional than the theme of alienated youth, especially youth alienated from vulgar dad. McInerney makes that theme into a medley with the tested theme of flight abroad into strange lands and self-discovery. ''He felt that the discipline would tone all of his being. It was his way of knowing himself.''

McInerney at this worst is nine yards better than another hot new author, Bret Easton Ellis, whose ''Less Than Zero'' is the worst novel since the invention of movable type. It is about yet another alienated Beverly Hills boy who likes cocaine about as much as he dislikes dad, who is in television. Alienated? The book begins: ''People are afraid to merge on freeways in Los Angeles.'' Get it?

McInerney's keen ear for trendy-babble does make him very funny in life as well as in fiction. When he went to Hollywood to sell ''Bright Lights,'' he says, ''They told me they were putting me up at Chateau Marmont and I said, 'Is that good?' And they said, 'Is it good? John Belushi died there!' '' We have not heard the last, or the best, from a man with an ear for stuff like that.