GOING TOO FAR By Tony Hendra Doubleday. 462 pp. $18.95 I THINK I DON'T REMEMBER By Art Buchwald Illustrated by Steve Mendelson Putnam. 350 pp. $16.95 IF YOU CAN'T SAY SOMETHING NICE By Calvin Trillin Ticknor & Fields. 257 pp. $16.95 AMERICA IS MY NEIGHBORHOOD By Willard Scott with Daniel Paisner Simon and Schuster. 252 pp. $16.95 SMALL COMFORTS More Comments and Comic Pieces By Tom Bodett Addison Wesley. 165 pp. $12.95

TOPICAL HUMOR often has a short shelf-life, especially when dispensed as parody or with a warning label that it's the stronger, more vindictive brand called satire. Sometimes this short life is because a public figure's peccadilloes or foibles -- which caused such hilarity in January when mocked by parody or driven to the absurd by satire -- provoke in June only silence or embarrassed throat-clearing when it's recalled that the skewered public figure is now either in jail, dead of the drink or reduced to driving a cab in Cleveland.

Satire's natural enemy is, of course, sentimentality. And since this is a nation composed largely of sentimentalists, it's reassuring, if surprising, to learn from Tony Hendra's Going Too Far that parody and its wicked cousin, satire, have been rescued and rehabilitated by the baby-boom generation.

Hendra goes even further and officially designates the new risibility as "boomer humor," which, he writes, "has received scant attention as a homogenous phenomenon, one with its own roots and special sounds, its own internal history and lineage."

Hendra settles on 1955 as the year when this renaissance began with the emergence of such comedians as the redoubtable Mort Sahl and the pungent Lenny Bruce -- although neither, by any calculation, could be counted as members of the boomer generation. But both were, Hendra asserts, harbingers of the boomer humor that "burned holes in people's minds when they first heard it . . . "

Before examining boomer humor more closely, it might prove useful to assess the recent works of two syndicated columnists who, through no fault of their own, were born a year or so too early for inclusion in the boomer generation. After reading, or re-reading, the columns reprinted in I Think I Don't Remember by Art Buchwald and If You Can't Say Something Nice by Calvin Trillin, I may not have had any holes burned in my mind, but I did encounter a variety of public figures, some real, some imagined, who were nicely scorched.

The last six years can only have been kind to Buchwald. As someone dependent upon the awful and the absurd for his livelihood, he must have received more material each day than he could possibly use with the arrival of his morning newspaper.

A typical Buchwald column takes note of some particularly wacky move by a high administration official -- say, a cabinet member; say, Attorney General Edwin Meese who -- along with the telephone company -- is a frequent Buchwald target. After briefly outlining the wacky move, Buchwald then checks it out by phone with his Top Source in the Department of Justice.

Under Buchwald's relentlessly ingenuous questioning, the Top Source not only confirms the latest gaffe but also explains and justifies it, thus reducing it to absurdity. Hyperbole and exaggeration are a humorist's primary tools and Buchwald's, honed by years of use, still seem as sharp as ever: "I've been randomly tested only three times -- once when I was drinking from a public water fountain outside Jesse Helms' office, once when I bought boxer shorts at Bloomingdale's, and once when I asked Attorney General Ed Meese at a press conference if he was having trouble understanding the Constitution of the United States."

Before Calvin Trillin began writing a weekly syndicated column, he wrote one column every three weeks for The Nation and was paid a sum that he claims was in the high two figures by the magazine's editor -- invariably and understandably referred to as "the wily and parsimonious" Victor S. Navasky.

It's to be hoped that Trillin will receive at least a footnote in the history of politics for having thought up the general purpose, fits-one, fits-all campaign slogan, which is, of course, "Never Been Indicted." I'm told the slogan's adoption is under active consideration by undeclared candidates in New York, Washington, Chicago and throughout Louisiana.

Trillin also deserves praise for having faithfully recorded the musings of Harold the Committed who, in the past, has served as a guidon to those in danger of straying from the path of political righteousness. Harold the Committed is also one of the very well informed and reads the entire Sunday New York Times by 2 p.m. If not finished by then, he makes himself read the editorials all over again.

Columnists, apparently a thrifty lot, often recycle their stuff into book form. The danger in this is that by the time their books are published their columns may have lost some of their immediacy. Fortunately, both Buchwald and Trillin also write about subjects of lasting interest, to paraphrase The Reader's Digest. Buchwald, for example, carefully analyzes the telephone company's billing system in an article titled, "#E3VLPBUT+X: $2.52" while Trillin provides a thoughtful answer "To the Chicken a` la King Question."

ON A different level, a very different level, is Willard Scott's America Is My Neighborhood, which was written with the aid of Daniel Paisner. Scott was one of the Joy Boys of Radio on WRC in Washington along with his partner, Ed Walker.

Scott is now -- as everyone knows unless they think switching on their television set in the morning is like reaching for a bottle of gin -- the weatherman on the NBC Today show where he wears funny hats and seems to enjoy his job immensely. Scott and his co-writer Paisner describe the places Scott has been and the people he has met -- all of them likeable and good-hearted and down to earth. It's very folksy and fairly syrupy and with any luck, the genial Scott may drop by your house.

The only self-proclaimed baby boomer among the writers considered here, other than Tony Hendra, is Tom Bodett of Homer, Alaska, who has recycled his columns into a volume called Small Comforts. Bodett steers clear of politics, writing instead in a homespun way about such homespun topics as potluck suppers, when will the snow melt, unlovable pets and haircuts.

However, he does predict, rather wistfully, that in years to come his generation of baby boomers "will make an institution out of being over the hill," and it will also be elderly in a different way -- less, well, you know, old.

He may have some support in this from Tony Hendra who, in Going Too Far, defines his generation as "people conceived during the war out of panic, those conceived after it out of relief, and those conceived for the next few years because no one had invented the pill."

Boomer humor was at first eyed with both horror and trepidation, Hendra says, because it dealt with "subjects that had hitherto been completely off-limits in popular comedy." It also disturbed people; made them sit up. Not only that, but the new humorists were pirating the traditional comedian's audience. These new people were "trespassing . . . these new people were Going Too Far."

Those who went too far, according to Hendra, were the aforementioned Mort Sahl and Lenny Bruce plus Terry Southern, Dick Gregory, Jules Feiffer, Second City, Saturday Night Live, The National Lampoon, Richard Pryor, the Smothers Brothers and about four dozen others. Hendra is a passionate advocate and a provocative, if prolix, writer who argues that the boomers will, as they reach full maturity, generate new and exciting forms of comedy.

At the end of this well-illustrated book, Hendra issues a manifesto of sorts: "We are the Boomers. We are a huge sprawling generation . . . held together by bonds we would be hard-put to describe, but which we know instinctively . . . We are the biggest and the best and the brightest."

But no longer the newest, Hendra might have noted, for only the children are always new.

Ross Thomas is the author of many crime novels, including, most recently, "Out on the Rim."