It's deja vu all over again in the music business.

In a season when some of the industry's brightest young stars have stumbled, ``greatest hits'' collections accounted for eight of the top 50 best-selling albums in the week ended Dec. 3, up from five albums a year earlier. Tailored to economy-minded baby boomers rekindling their interest in music, ``best of'' albums are increasing the profits of record companies skilled at repackaging old material in new formats. In most cases, several new songs are added to the mix to command radio play and exposure on MTV.

``Even customers who have many of an artist's top albums are buying them, because the collections bring together a performer's best songs in one place,'' says Ivan Lipton, president of Strawberries Inc. of Milford, Mass., which operates 165 stores under the names Strawberries and Waxie Maxie's.

A decade ago, such albums were often consigned to the cheapie bins of discount stores. Today, record companies are providing the marketing fireworks once reserved for new albums. Madonna's ``Something to Remember,'' for example, has a multimillion-dollar promotional budget that includes print ads, radio spots and a 30-second television commercial that has aired on the morning news shows.

The album, released on Maverick Records, a joint venture of Time Warner Inc., Madonna and music executive Freddy Demann, has quickly become a big seller. Fans have scooped up about 368,000 units since its October release _ despite the fact that 11 of the album's 14 ballads date back as far as 1984 and Madonna has had other ``best of'' albums.

Certainly, some greatest-hits packages fall flat. Although the Michael Jackson double-album ``HIStory Past, Present and Future Book 1'' has sold 1.7 million units, it never generated the fan support that retailers were hoping for to lift their summer business. The album was initially conceived as a ``best of'' collection before being released as a combination of new and old songs. By contrast, the Beatles' new two-disk set may be the most lucrative greatest-hits collection yet, with first-week retail sales of about $24 million at a retail price of about $25.

Elaborate packaging can go a long way. A four-CD collection from rocker Rod Stewart titled ``Storyteller,'' complete with a 24-page color booklet, has sold 680,000 units since its release in 1990, despite its $70 retail price. Six months after its debut, Warner Bros. Records, a unit of Time Warner, released ``Best of Storyteller'' for fans who wanted to purchase only one disk. That album has since sold nearly two million copies domestically. ``Rod's career didn't need a pickup _ I would never release an expensive package when a career is lagging _ but `Storyteller' created a big stir, and it's still in print,'' says Arnold Stiefel, the singer's manager.

Greatest-hits collections also enable record companies to cash in on performers who don't have enough material for a whole new record. In September, Columbia Records, a Sony Corp. unit, released Michael Bolton's ``Greatest Hits 1985-1995,'' on which five of the 17 tracks were new. The album has already sold about 770,000 units.

To promote the collection, Columbia arranged a guest spot on the talk show ``Oprah'' for Mr. Bolton, as well as livestore appearances in Los Angeles. ``Michael is still a heartthrob type, so we're giving him an opportunity to reach his fans,'' says Jay Krugman, Columbia's vice president of marketing.

Indeed, 10 fans have been picked at random to savor a private satellite-delivered concert that Mr. Bolton will give on Thursday. The concert, which is being produced in conjunction with Lifetime Television, will probably cost in excess of $250,000. According to Mr. Krugman, thousands of fans called an 800 number to enter the contest.

Although Mr. Bolton and Madonna are still big stars, greatest-hits collections are also being used to relaunch careers that have gone stale. The English pop metal band Def Leppard, for example, issued two of the biggest-selling albums of the 1980s. Largely forgotten in recent years, the band returned to the recording studio this past spring and finished an album tentatively titled ``Slang.'' At that point, however, the band's managers, Cliff Burnstein and Peter Mensch, partners in New York-based Q Prime Inc., decided that Def Leppard needed to rekindle fan interest and would be better served by issuing a greatest-hits collection first. The resulting album, ``Vault,'' has sold about 227,000 units since its Oct. 31 release by Mercury Records, a unit of PolyGram NV. The offering includes one new song supported by a music video.

``What we've done is prepare fans for their new sound with one song. In the end, we hope that this will make them a big name again,'' says Mr. Burnstein. For its part, PolyGram has hit the jackpot with greatest-hits packages in the past: Last year, a Bon Jovi ``best of'' album was the company's biggest seller world-wide.

Although some music executives say that greatest-hits collections can hurt the value of an artist's earlier releases, Val Azzoli, president of Time Warner's Atlantic Records, says that a Led Zeppelin four-disk set it issued in 1990 didn't have any impact on the sale of the group's earlier albums in subsequent years _ even though Atlantic sold more than one million units.

Earlier this fall, Atlantic released a greatest-hits collection from pop singer Debbie Gibson. The reason: Ms. Gibson had a new album coming out in July on a different label, and Mr. Azzoli wanted to piggyback on that album's publicity.

The Debbie Gibson greatest-hits album has already sold more than 30,000 units, according to SoundScan Inc., a market research company in Hartsdale, N.Y.