It's been 18 years since the Beatles went their separate ways 18 years for memories of Beatlemania to fade, for the tunes to grow stale, for the music to be relegated to Golden Oldies stations.

That could have happened, but it hasn't. Not by a long shot. If anything, the Beatles of yesteryear enjoy more mainstream appeal today than they did when the band broke up in 1970.Radio stations from the adult contemporary KSL to the hard rock KRSP play the same Beatles songs. The appeal of the music crosses all socioeconomic boundaries, all musical tastes.

Yuppies driving Saab Turbos are Beatlemaniacs. Teenagers driving their dad's family sedan are Beatlemaniacs. Women. Men. Rich. Poor. Black. White. The Beatles and the songs they wrote are still the standard against which all other pop music is measured.

And it never grows old.

The release last year of 12 Beatles albums on compact disc fueled a renewed interest in the Beatles. Not that interest had ever waned that much. But it offered a new dimension for the classic sounds.

Capitol Records has released the final installment of the compact disc project: "Past Masters Volumes I and II," newly compiled collections of non-album tracks and B-sides of singles. It's the 2-CD collection that Beatlephiles have been salivating for for a long time.

Volume I covers the band's early history, from the first single, "Love Me Do," in 1964, to "I'm Down," the B-side to 1965's "Help." Other tracks include the German language versions of "I Want to Hold Your Hand" ("Komm, Gib Mir Deine Hand") and "She Loves You" (Sie Liebt Dich").

Volume II opens with the 1966 single "Day Tripper" and ends with the 1970 bossa nova tune "You Know My Name (Look Up the Number)," which was actually recorded as an instrumental in 1967 before John Lennon and Paul McCartney added vocals in 1969.

The collection also has five No. 1 hits, including the group's best-charting record, "Hey Jude," which topped the Billboard list for nine weeks. Other No. 1 hits include "Paperback Writer," "We Can Work It Out," "Get Back" and "Let It Be."

Other familiar tunes include "Revolution" (the Nike sneaker version), "Lady Madonna," "Day Tripper" and "The Ballad of John and Yoko," all of which were on the "Hey Jude" album released in the United States, but not released in Britain.

(Capitol is only releasing compact discs of the British versions of the albums. "Hey Jude" was never an album in England, and is therefore incorporated in this collection.)

Both CDs offer a splendid sampler of the evolution of the Beatles, from the playful innocence of "I Want to Hold Your Hand" to the ear-splitting screech of "Revolution."

The CDs offer a lot of unfamiliar tracks or rare versions of familiar tracks. The version of "Love Me Do" features Ringo Starr on drums. The version on the "Please Please Me" compact disc, which was recorded a week later with session drummer Andy White, is the one most people know.

Like the other Beatles CDs, these compact discs offer the clarity and purity that makes listening such a gratifying, often jubilant, experience. It also re-affirms the music of the Beatles, as a whole, as the best pop music ever written.

The tracks on "Past Masters Volume I" include: "Love Me Do," "From Me to You," "Thank You Girl," "She Loves You," "I'll Get You," "I Want to Hold Your Hand," "This Boy," "Komm, Gib Mir Deine Hand," "Sie Liebt Dich," "Long Tall Sally," "I Call Your Name," "Bad Boy," "Yes It Is" and "I'm Down."

"Past Masters Volume II includes the tracks "Day Tripper," "We Can Work It Out," "Paperback Writer," "Rain," "Lady Madonna, "The Inner Light," "Hey Jude," "Revolution," "Get Back," "Don't Let Me Down," "The Ballad of John and Yoko," "Old Brown Shoe, "Across the Universe," "Let It Be" and "You Know My Name (Look Up the Number)."

With the release of both compact discs, all of Capitol-EMI's originally released albums and singles by the Beatles are available on compact disc.