Ross W. Duffin presents an engaging and elegantly reasoned expose of musical temperament and its impact on the way in which we experience music. An historical narrative, a music theory lesson, and, above all, an impassioned letter to musicians and listeners everywhere, ''How Equal Temperament Ruined Harmony'' possesses the power to redefine the very nature of our interactions with music.For nearly a century, equal temperament - the practice of dividing an octave into twelve equally proportioned half-steps - has held a virtual monopoly on the way in which instruments are tuned and played. Duffin explains how we came to rely exclusively on equal temperament and along the way, he challenges the widely held belief that equal temperament is a perfect, 'naturally selected' musical system, and proposes a radical re-evaluation of how we play and hear music.