"The reason I like monster movies," an anonymous child remarked, "is cause they help me escape from reality." What does it say about this happy age of ours that even little kids are thinking this way -- that reality is something to be escaped from?

Well, never mind what it says, because it's probably too depressing, and the kid's observation is only a fleeting comment during "SPFX: The Empire Strikes Back," a one-hour special on CBS tonight (Channel 9 at 8 p.m.), for all the zillions who have seen the two "Star Wars" movies and for the six or seven party poopers who haven't.

It is a confident and clever magician indeed who can reveal his tricks and still not spoil the illusion, which is what the producers of the program and a battalion of special effects technicians manage to do on "SPFX." It doesn't hurt at all to learn that the Millenium Falcon is, at most, four feet wide (and sometimes only two inches wide), or to behold a pale Wookie, actor Peter Mayhew, wearing none of his Chewbacca outfit but the two big dark circles around his eyes.

In outtakes, the terrible, shaggy creature who lives in a cave on Hoth is revealed to be only a tall actor who has such difficulty walking in his costume that he repeatedly topples face-forward, into the very earthly snow of a Norwegian glacier, where many "Empire" exteriors were shot. Yoda, the liter-sized Jedi master, keeps most of the secrets about the force that gave him life on the screen, but we do see him in the construction stage and discover that his eyes were modeled after those of Albert Einstein. Al would certainly get a kick out of that.

The film -- produced and directed by Robert Guenette -- also takes cursory looks at such landmarks of cinema fantasy as Willis H. O'Brien's still awesome "King Kong," Ray Harryhausen's cop-munching "Beast From Twenty Thousand Fathoms" and those wonderful coffee percolators that Universal dangled on wires so that Flash Gordon could go from hither to yon to Mongo. The elements of stop-motion photography have been grasped too, by filmmakers as young as 11 or 12, as a few student-made space epics demonstrate.

Mark Hamill, looking as though he is still lost somewhere in the Dagobah system, narrates, from an unfortunately flat and sappy script by Richard Schickel (probably the most humorless of all modern movie critics now that Renata Adler has left the trade to go into poison penmanship). One of the script's virtues, though, is that it takes pains to cite as many of the techniques by name as possible -- perhaps an outgrowth of the generosity for which filmmaker George Lucas (seen in a few shots) is known.

These people are workers in the greatest dream-factory that has existed since the days when MGM hoarded geniuses by the dozen to make musicals by the score. The quality of reality may be drastically on the decline, but the "Star Wars" movies are upholding the quality of escape.