Amazon.com essential recordingPerhaps sensing that their Collected Works felt a bit skimpy with only tracks from their five studio albums included, this collection features 15 previously unreleased tracks including live material, demos, and studio outtakes previously unreleased, alongside a substantial number of the duo's hits. Early demos point up Paul Simon's excellent acoustic guitar fingerpicking and emerging songwriting. "The Sound of Silence" is featured in its original undubbed form and the later overdubbed band version that became the hit. The duo's strongest work is all here and the addition of several B-sides left off their collected works makes this a helpful collection to have around. --Rob O'Connor