Does the world need another version of the Beach Boys' Pet Sounds? It's one of popular music's most sublime works, and one of the most reissued since its release in 1966. There's the first CD version from 1990 with three bonus tracks, a 2001 remastered take, a 2006 40th anniversary edition, a four-disc 1997 sessions box and now Pet Sounds (50th Anniversary Edition), another four-disc collection of alternate versions, live cuts and leftovers.

So, do we need another Pet Sounds at this point? Depends if you happen to think it's one of the best albums ever made.

Most fans will already have much of the material gathered here (the original album is again collected in both mono and stereo); only a handful of the studio cuts didn't show up on the excellent 1997 box. All but 14 of the 104 tracks have been previously released, and the majority of the unreleased cuts are live versions of Pet Sounds songs spanning 1966 through 1993. That doesn't give much incentive for people who've bought the album two or three times before. (The original album is remastered, and there's a new 5.1 surround mix included in the expanded "Collectors Edition," but the sonic upgrade at this point is minimal.)

Still, Pet Sounds has become such a foundation of so much modern music -- everything from indie and hip-hop to psychedelic and pop music have been influenced by the record -- that it's still fascinating to hear Brian Wilson piece together his masterpiece, with the other Beach Boys, studio pros and all the voices in his head working together toward a common goal. Whether it's early fragmented takes of classic songs like "Sloop John B" or the various dialogue between producer and musicians, the four discs sketch a portrait of not only one of the twentieth century's greatest artists but also his most celebrated piece of art.

Instrumental versions of the songs give one perspective; a cappella tracks give another. But Pet Sounds truly comes together when the pieces interlock. Historians and longtime fans have celebrated these alternate takes and session outtakes before, but nothing provides a rush quite like the 36-minute album at the center of all the attention. Fifty years later, the 13 songs gorgeously flow like few records before or after it. It's one of pop's most perfect and enduring albums. "Wouldn't It Be Nice," "Sloop John B," "God Only Knows" and "Caroline, No" were the singles, but there's not a disposable track here.

The 50th Anniversary Edition is built on the original Pet Sounds, its history and its legend, so the key set is the four-disc one (there's also a two-disc version that collects the album and highlights from the sessions). The earlier box got to most of this material first, so only completists will really need to upgrade. But for anyone interested in pop music's evolution over the past five decades, or how one of the best records of the twentieth century was made, there's not a better place to start.

See the Beach Boys in the Top 100 Rock Albums of the '60s