If you're a fan of Wagner's Ring Cycle, or want to find out more about it, then this is for you!  This single program CD contains all 16 hours of the operas' audio synchronized with scrolling musical score and libretto in German and English.  It's a wonderful interactive study guide and an amazing piece of work.  It also contains details of the synopses, character descriptions, symbols, leitmotifs and images, as well as a comprehensive bibliography.  It's all very accessible and user-friendly.  Have fun!