Procol Harum.

P... R... O... C...

Perhaps the reason British rock band Procol Harum has basically disappeared from musical history is that its name is just too difficult to comprehend. When questioned about their knowledge of the group's catalogue, even the most open-minded, die-hard music fans often respond with, "Wait, spell that out for me." Or maybe a little "WHAT Harem?" And there's always the classic "Procto WHAT?"

But describing its sound is even more difficult than understanding the band's name, and the answer of "orchestral, psychedelic rock 'n' roll with Hendrix-esque guitar and strange lyrics" is kind of flawed. That's a lot of adjectives, yes. This is a band that could easily collapse into a musical catastrophe.

Between 1967 and 1977, the group released 11 albums, but none of those sums up Procol's balance between Bach and rock better than its first four discs. Fortunately, for those of us who arrived a few decades late, the Metro label has squished the first four Procol Harum albums onto one convenient, two-disc set titled The First Four. These albums need to be heard in order to realize that the group not only doesn't collapse, it actually works very well.

It would be wrong not to acknowledge that Procol Harum is sometimes remembered for one timeless single, the slow, organ-driven "A Whiter Shade of Pale." Interestingly, that song doesn't even appear on The First Four -- and it's better that way. Instead of overshadowing 35 brilliant tracks with the one song that a casual listener with a short attention span might only listen to, The First Four immortalizes a set of forgotten records that still deserve attention.

The group's self-titled first album immediately introduces the unorthodox Procol sound with "Conquistador." The song rocks and impresses at the same time by blending underrated guitarist Robin Trower's heavy riffs with Gary Brooker's classically influenced piano. Even though some of its tracks feel underdeveloped, the album culminates with the explosive "Repent Walpurgis," a dramatic instrumental that might have worked better as part of a larger piece but should be recognized for sounding like post-Syd Barrett Pink Floyd about four years early.

As if the band realized the not-fully-realized nature of its first album, Procol's Shine On Brightly, the second album in the collection, does develop some of its songs more thoroughly. The title track rocks with an elegance characteristic of the group's sound, while "Skip Softly (My Moonbeams)" features two extended endings that could have been passed off as goofy but actually add to the song's psychedelic quirkiness.

Most impressive, however, is the album's closing, sidelong (remember vinyl?) suite, a 17-minute exploration of inner thought and insanity that actually keeps the listener's attention the whole time. This is complicated prog rock at its finest and, again, several years earlier than expected.

After all that, Procol Harum continues to shine on indeed with A Salty Dog. The title track of the third album is another underrated element of the group's history, an epic composition that truly captures the spirit of an emotional sailing adventure.

Elsewhere on this album, the band explores an even more diverse range of musical territory, from the acoustic brightness of "Boredom" to the bare-bones blues of "Juicy John Pink."

The collection closes with Home, an album that, in comparison to the others, sounds both different and similar at the same time. No other record here kicks off with the kind of raw rock energy contained in the Trower-composed opener, "Whisky Train." Still, most of the rest of the album typifies the Procol equation of mixing creative, memorable melodies with the strange, often disturbing words of lyricist Keith Reid. Examples include "Still There'll Be More," the catchiest song about absolutely hating someone ever written, and "Your Own Choice," a musically peppy pop song in which the singer loses faith in the entire human race.

Procol Harum fans -- I know you're out there somewhere -- could attest to the fact that there's plenty more to write about a group that seamlessly blends distorted chords, complex string arrangements and graveyard imagery.

Even if the group's name will never make sense, the easiest path toward an understanding of Procol Harum's music is The First Four.