Like a pianist sitting down at the keyboard to tackle Prokofieff or Messaien, Stuart Isacoff --- himself a pianist and the editor of Piano Today magazine --- faced a daunting task when he decided to write this book. He sought to write for the general reader about an abstract and highly technical musical subject, one to which even many professional musicians give little thought as they go about their daily work.

"Temperament" in the sense Isacoff intends stands not for the antics of high-strung performers under pressure, but for the systems of tuning that have governed western music since its birth well over 2,000 years ago. Disputes and debates over the centuries on this subject have been long and heated, and even today there are pockets of guerilla resistance here and there to the generally accepted victory of "equal temperament," a compromise of convenience that ultimately produced our familiar "do-re-mi-fa-sol-la-ti-do" scale system.

Isacoff's solution to making this basically dry topic into a readable book was to produce something that is part elementary theory text, part cultural history and part personal observation. It is a generally successful job, but perhaps not exactly in the way Isacoff intended. He is a sprightly writer and an industrious researcher and he kept his book short, evidently fearful of producing a ponderous technical tome that would be impenetrable to any but expert readers.

The basic long-running conflict was between proponents and opponents of theories first advanced by Pythagoras, the pre-Christian Greek sage, whose divisions of the musical octave into its constituent tones were supposedly governed by supposedly immutable natural laws that did not admit of variation. Later theorists insisted that Pythagoras' work resulted in tiny imperfections that rendered some musical intervals dissonant rather than consonant. Their research ultimately produced our present-day system of (admittedly imperfect) "equal temperament." Isacoff has researched this academic quarrel thoroughly and come up with entertaining character sketches of the main combatants. In trying to relate the basic debate to world history in general, Isacoff strays rather far from his subject, but the digressions are in themselves interesting and serve to keep the nonmusical reader turning pages.

Robert Frost reportedly wrote somewhere that there are three great things in life --- religion, science, and gossip. Isacoff's book has enough of each to satisfy a diverse readership. Among those not usually thought of as musicians who contribute to his story are Isaac Newton, Rene Descartes, Jean-Jacques Rousseau, Giordano Bruno, and Vincenzo Galilei, father of the immortal astronomer. Surprisingly, J. S. Bach, whose Well-Tempered Clavier is generally credited with establishing the supremacy of "equal temperament" for modern ears, makes only a cameo appearance for a couple of paragraphs near the very end of the book.

Along the way, however, we get entertaining and generally relevant comparisons between systems of musical tuning and things like the development of perspective in painting or the tension between allegedly divinely-ordained laws and real human experience. It may be music history "lite" but it covers the ground and provokes thought.

The equal temperament system is now so fully entrenched in our ears and in the working life of musicians that any other tuning system seems inconceivable, except to specialist antiquarians like those in the early music movement. But it is worth remembering that a lot of ink and sweat was spilled to establish our present system, and that compromises and sacrifices had to be made to make it work at all. It is a lesson that fanatic politicians might study to their profit.

Remember that the next time you sit down at the piano and play a scale.