If you're down with progressive hip-hop and aren't hip to the sounds of the collective formerly known as Solesides, you need to check out this two-CD retrospective. DJ Shadow, Chief Xcel, and the Gift of Gab (aka Blackalicious), Mack B. Dog, and Lateef and Lyrics Born (aka Latyrx) are among the finest artists in Bay Area hip-hop, laying the groundwork that forms the foundation of the West Coast alt-rap scene. With a cratedigger's attention to detail, you can hear Shadow's skills all the way back on 1993's "Entropy," while Blackalicious' dextrous lyrics on 1994's "Lyric Fathom" are evidence of the clique's trademark abstract expressionist rhyme style. For those who have followed the Solesides crew's careers, there are plenty of unreleased cuts, rare B-sides, and remixes here to make this a worthwhile investment. For those who haven't, freestyle throwdowns like "Lateef's Freestyle" and posse cuts like "Blue Flames" are ample evidence that this is one of the most potent crews in hip-hop.