<HTML>David A 'well temperament' (perhaps a better term would be good temperament) was thought by Werckmeister, Neidhardt, and Vallotti, to be one in which the circle of fifths was 'closed' ie no wolves! and playable in all keys.  Major and minor intervals varied in size according each system and favoured the more common scales and triads (less sharps & flats) yielding 'key colour'.  Heavily tempered intervals were placed in keys with more sharps and flats. Equal temperament is of course a good/well temperament but I would agree with Ed that (pre 1800?) music sounds so much better with an irregular temperament. It's interesting that Werckmeister wrote ways 'wohltemperirt stimmen' (to tune well-tempered) nearly a third of a century before the first collection of 24 Preludes and Fugues were written (1722) This is as succint as I could get from my buckets of notes! Rob Thornton </HTML>