Add "redefining how rock groups age" to the list of R.E.M.'s accomplishments. Time was, a reference to "the R.E.M. sound" had a single meaning: jangly, Byrds-inspired guitar-rock, paired to evocative but difficult-to-discern lyrics. A band rarely exerts such far-reaching influence that its name can stand in for an entire school of an era's music, and a band simultaneously capable of moving beyond such a narrow definition is rarer still. Yet, now in its 21st year, R.E.M. continues to surprise. The group has never been afraid of new things, but few could have predicted the creative rejuvenation it's experienced in recent years. Perhaps forced to experiment by the departure of drummer Bill Berry and longtime producer Scott Litt, R.E.M. has recently crafted sounds beholden neither to its own past nor to current trends. Despite the turmoil, since the release of 1998's Up, R.E.M. seems to be coming into its own again. The new Reveal continues and expands upon Up's experiments, relying less upon a single mood. Lush arrangements once again strike a balance with spare, even harsh percussion—check out the whistles on "Saturn Return"—and the band works the tension to great effect. At moments, only Michael Stipe's familiar vocal style serves as a solid connection to R.E.M.'s past. For all its daring, Reveal still ranks among the group's most instantly winning albums, the kind whose poppiest pleasures, like "All The Way To Reno (You're Going To Be A Star)" and the single "Imitation Of Life," eventually fade into the album's overall beauty. Stipe has said that R.E.M. nearly dissolved after Up's completion, but, with any luck, Reveal has helped resolve any internal problems. Already surpassing the natural life expectancy of most acts, the group shows no sign of growing any less interesting as the years pass.