By Wu Tang Forever, their long-delayed, massively anticipated second album, the Wu had become less a crew than a small country, with dozens of central and auxiliary members, and rap styles so twisted they seem like another, private language. Without even a hint of anything for radio or casual listeners to latch onto, Wu-Tang Forever sprawls out for nearly two hours, and--taken as pure sound--it's about the most avant-garde U.S No. 1 album ever, with deliberately bizarre production (out-of-tune and off-rhythm loops, even what sounds like a string quartet) and relentless torrents of cryptic, furious words. It demands repeated listens and careful attention to begin penetrating the mysteries of this dense, passionate, unique piece of work.--Douglas Wolk