Tom Shales prefaced his review of the television movie "Extreme Close-Up" {Style, Oct. 22} by saying that "TV about TV is still fairly rare; the medium tends to ignore its own existence." While I don't dispute Shales's subsequent review, his premise could not have been more off the mark.

Television is increasingly obsessed with its own existence. In one obvious example, David Letterman constantly spoofs his own genre -- the TV talk show -- and pokes fun at television and the fact that he's on it.

The "It's Garry Shandling's Show" has a theme song that begins "This is the theme to Garry's show." It is about a guy with a TV show doing a TV show, and Shandling constantly talks to the audience and introduces them to characters in the show.

"Moonlighting" was credited with "breaking the wall" with its repeated self-references. Bruce Willis would make comments like, "I'm just an actor reading lines." "Moonlighting" characters directly addressed the audience, letting us know that they knew that they were a TV show.

Still another example of this self-consciousness is an episode of "Murphy Brown" that concerned a TV show based on Murphy (called "Kelly Green"). In the episode, Murphy makes a guest appearance as herself on the new show. In the denouement, Connie Chung makes a guest appearance on "Murphy Brown" and chastises Murphy for her appearance on "Kelly Green." Chung adds that she would never do a guest shot on a TV comedy series.

Even a conventional sit-com such as ABC's "Growing Pains" is self-aware, occasionally poking fun at other television shows. Kirk Cameron's character, Mike Seaver, for example, gets a job as an actor in a TV series. The greatest thrill, he explains to his family, is that it's a series on ABC.

In a more serious -- and disturbing context -- the September issue of Harper's magazine noted that during the 1988 political campaign, television devoted half of its campaign coverage to television's coverage of the campaign.

Television is watching itself. The only question is whether Tom Shales is watching. -- Eric I. Greenberg