Bach's Well-Tempered Clavier is a well-known work consisting of 24 preludes and fugues, in each major and minor key. Performers and musicologists have long wondered exactly what was meant by well-tempered . It means, of course, that the instrument is meant to be tuned in such a way that the different pieces in all 24 keys sound  pure and agreeable, something that Bach's obituary said he achieved. Yet not until recently has it been possible to tune a keyboard instrument in this manner. In 2005, musicologist Bradley Lehman published two articles in Early Music, entitled  Bach's extraordinary temperament: our Rosetta Stone , where he lays out what he thinks would well-temper a keyboard. And this recording is the first Well-Tempered Clavier to use this tuning. For more information, see www.larips.com.    If it were only for the arcane question of tuning this recording would have little more than intellectual interest. There are other factors that make it, perhaps, one of the finest available recordings of this work. First, Peter Watchorn brings to this recording his more than 35 years  experience playing Bach. Watchorn is a consummate performer, not only injecting energy and vibrancy into his playing, but also approaching this recording less as a collection of preludes and fugues than a single work consisting of 48 movements. This large-scale approach combines with a cyclic approach as Watchorn tacks a 49th movement at the end: a da capo performance of the opening prelude, which shows that the work has come full-circle.    But there's more. Watchorn performs this recording on a pedal harpsichord, which might be considered the string version of an organ. The pedal harpsichord has pedals, like an organ, that play low notes, allowing the performer to approach Bach's intricate counterpoint in a different manner. The sound of this instrument is delicious; with a full range of bass notes and treble sounds, it is a truly complete harpsichord. A copy of a 1646 Ruckers, this har --http://www.musicweb-international.com/classrev/2006/Dec06/Bach_Watchorn_MO0201.htm