BOOK REVIEW : Witty Writing Is Straight From the Heart : THE EASY WAY OUT <i> by Stephen McCauley</i> : Simon & Schuster; $20; 298 pages

Some of the most gratifying novels are those that refuse to take themselves seriously even as they work sensitive emotional terrain.

In this sort of book the writer seems to play the story for laughs, entertaining the reader with witty dialogue and amusing scenes, yet something significant always seems to be going on just beneath the surface.

The things left unsaid are just as important as what’s on the page, for the omissions compel the reader to get involved with the book without even knowing it--to see parallels between relationships, to heed roads not taken, to try to figure out why one character flourishes and another dwindles.

The writer, in essence, is a seducer, slipping in social commentary and observations so deftly that readers are likely to believe they came up with them on their own.

Stephen McCauley’s “The Easy Way Out” is such a book, a comic novel that explores the difficulties inherent in close relationships by making light of them.

It begins with the narrator, a Boston-area travel agent named Patrick O’Neil, being awakened in the middle of the night by a telephone call from his overachieving younger brother, Tony, who is having cold feet about his upcoming marriage to his long-time girlfriend.

Patrick quickly worms out of Tony the embarrassing fact that he’s fallen in love with another woman, leaving Patrick feeling both envy at Tony’s head-over-heels passion and satisfaction at the chance to go into his atrophied big-brother routine. “With my younger brother,” Patrick tells us, “I try to grab the advantage immediately.”

Patrick, against the advice of all his friends and relations, is instantly in the thick of Tony’s dilemma, lobbying mildly for Tony to call off the engagement.

Patrick surprises himself at the depth of his involvement--he hasn’t been close to Tony for years--but its roots are transparent to the reader: Patrick, who is gay, is projecting onto Tony his ambivalence about his live-in lover, Arthur, and indeed about most long-term relationships--that between Patrick’s and Tony’s parents, for one.

Although James and Rita O’Neil are an unhappy couple and do little but fight, it’s clear their marriage will last unto death, if only for reasons of inertia. Getting divorced, Patrick says, is something his parents think of as an option whose time has come and gone, just one more lost opportunity in a sea of disappointments.

What Patrick wants to avoid at all costs, of course, is duplicating his parents’ mistake, and he is under enormous pressure to make up his mind about the relationship after Arthur (whom all the O’Neils proclaim to be much too good for Patrick) decides that he and Patrick should buy a house together.

Patrick goes along with Arthur’s plan, although only with a great deal of passive aggressiveness, since he can deal with Tony’s ambivalence much better than with his own. Patrick starts sleeping on the floor at home, ostensibly for back problems, resumes an old affair in New York and generally exhibits behavior verging on the pathetic.

Yet he manages to remain charming, for he is shrewdly self-deprecating and astute about everyone else’s troubles. Even at work, he’s more counselor than travel agent, spending his time not booking reservations but talking clients into staying home and coping with personal problems.

“The Easy Way Out” resolves itself exactly as it should, which is to say through a slew of painful compromises with which no one is really happy. McCauley--whose first novel was the widely acclaimed “The Object of My Affection”--does provide one ray of hope, however; Patrick’s older brother, Ryan, a recently separated teddy bear of a man, and Patrick’s mentor at the travel agency, the fiercely independent Sharon, have fallen in love.

They seem at first to be an unlikely couple, but there are hints that the relationship will work: Love, as Sharon notes, is based largely on fantasies, leading her to conclude that love works “when two people are deceiving themselves in the exact same way.”

Lines like that--and they abound in this novel--are only icing on the cake, for “The Easy Way Out” is more about character than consciousness. McCauley is a sympathetic, responsive observer of his fellow humans; he never patronizes (well, almost never) and he never judges harshly, knowing that only hypocrites cast the first stone.

McCauley, best of all, is unpretentious, a rare trait in young novelists and one that serves him well. “The Easy Way Out” seems to have been written straight from the heart, a heart that’s felt its full share of pain and uncertainty.