There was a time when you could only be a closet Abbott & Costello fan.

Laurel & Hardy were revered as the quintessential classical comedy team, while Abbott & Costello were considered knockabout comics ranked only slightly higher than the Three Stooges.But the laugh is on people who made Abbott & Costello fans feel inferior.

Somehow the antics of Bud Abbott, the tall, lean straight man who sometimes wore a mustache, and Lou Costello, his short, tubby foil who was smarter than he acted, sillier than he needed to be and ultimately had to take a slap in the face, have managed to stand the test of time.

Their humor may not be as universally appreciated or subtly sophisticated as Laurel & Hardy, but aside from them Abbott & Costello have proven to have better staying power than any other comedy duo in history, including Martin & Lewis and Rowan & Martin.

But why?

After all, their humor came from burlesque and vaudeville routines that they recycled endlessly through their nearly 50 movies, their radio programs and their TV appearances.

A partial answer is revealed in the new release "The Best of Abbott & Costello Live," from Warner Home Video ($19.98, 58 minutes). This is a compilation tape of live performances from the team's appearances on "The Colgate Comedy Hour," on which they were monthly hosts from 1951-54.

A couple of those "Colgate" programs are available, complete with commercials, on various video labels, but this "Best of" tape is simply a collection of Abbott & Costello's familiar routines gleaned from quite a number of the show's episodes. And the kinescope-to-tape transfer is of much higher quality than other tapes I've seen.

There are some guest stars - Charles Laughton, George Raft - but mainly the concentration is on 20 familiar Abbott & Costello routines, such as Pvt. Costello learning Army drills from Sgt. Abbott, Abbott teaching Costello how to play craps, Abbott exchanging two tens for a five, and, of course, the classic "Who's on First" banter. Some moments here are better than others, but there is no question that the boys were having a great time while doing these shows. And so was the rest of the cast. And the audience.

That sense of fun is contagious to the video audience, especially when the so-called "Golden Age" of live television is represented by flubs and goofs - and there are many here - providing unexpected laughter as Costello and friends try to cover their mistakes or stop laughing at themselves.

But what really makes these tired, old skits work is the impeccable timing of both stars. Bud Abbott was the perfect straight man and his sense of comedy was no less than Costello's - it's just that Costello got to deliver all the punchlines. And Lou Costello was, of course, the master of comic delivery and that mastery is obvious throughout this tape.

It should also be remembered that this was in the fading years of their careers. In 1951 when they first appeared on "The Colgate Comedy Hour," Abbott was 56 and Costello 45. Within five years they would make their last appearance together. And within eight years Costello would be dead.

This tape does have some drawbacks. There are no transitions to tie the routines together, there are no dates to allow time reference and some of the bits have obviously been interrupted in the middle.

But fans of the duo will love "The Best of Abbott & Costello Live," and those who are not may enjoy some of the still-funny routines and a madcap moment when Costello conducts an orchestra and wreaks havoc.

This is one instance when I hope we'll soon see a sequel.