Once a familiar sight atop the nation's TV sets but wary of going the way of the rabbit-ears antenna, TV Guide intends to be a comprehensive guide no longer.

The iconic 52-year-old magazine, which rode TV's popularity to become one of this country's best-read periodicals, announced plans last week to revamp completely. It will ditch most of its listings in favor of lifestyle and entertainment features with only selected programs showcased.

It also expands from its digest format to standard magazine size as of its Oct. 17th edition, slashing weekly circulation by nearly two-thirds, promising advertisers just 3.2 million readers, from a peak of 20 million in the early 1970s.

"This is an important moment in the history of TV, pop culture, and publishing," former TV Guide TV critic Jeff Jarvis noted on his blog, buzzmachine.com. "This is the official end of the mass market."

Like the networks it covers, TV Guide has seen its audience age and decline, fragmented by increased competition and channel surfing. Ironically, the publication that once boasted in ads that it was vital reading because TV was getting more complicated, is now being forced to change dramatically in part because TV got more complicated.

Many viewers, especially younger ones, have grown accustomed to consulting listings online or onscreen via cable systems and satellite TV providers along with digital video recorders such as Tivo.

TV Guide's listings, printed a week or more ahead of time, also were facing the challenge of becoming obsolete, or at least unwieldy, because of the proliferation of channels, which threatened to overwhelm the once neat and tidy grid system of listings, turning into a making it look more like a telephone book than a program guide. At the same time, their reliability was challenged in recent years by networks' last-minute competitive schedule changes

Calling TV Guide "the most trusted brand in television," and "an integral, iconic part of American life for more than 50 years," Rich Battista, chief executive officer of parent company Gemstar-TV Guide International, said in a statement that the revamped magazine "will be a more relevant and vital part of viewers' lives for years to come."

John Loughlin, president of the TV Guide Publishing Group, cited research showing readers want "a big weekly magazine that is focused on TV shows and characters" while enabling them to "find shows that appeal to their interests and moods," which is why only a quarter of the publication will be devoted to program highlights and listings, as opposed to the current 75 percent.

The latest overhaul of TV Guide is emblematic of what Jarvis calls "one size fits all" media being overtaken. "It's really indicative of where our culture has gone. We all go where we want to go," Jarvis said by phone. "The whole notion of a TV Guide, which was so right for its time ... is the exact best indication of how far past that we've gone."

A 2004 study of 1,200 households with digital cable found one in seven TV viewers used an interactive program guide "very frequently" in choosing what to watch.

But it's still part of popular culture: Tagged "The Guide" in a 1993 episode of "Seinfeld," the magazine was an obsession of aging crank Frank Costanza and a dweeby would-be suitor of Jerry's pal, Elaine Benes.