A layman's primer on the psychology and history of the human response to music. Jourdain, a California composer and pianist, goes at his subject with the zeal of an impresario, approaching music from as many different angles as he can think of: the anthropological, the biological, the aesthetic, the moral, and the physical. The book that results from his discoveries swarms with information. We learn that ``all in all, it took some 500 million years--well over a hundred million generations of animals--to evolve from the first hint of sound to an ear that can fathom Don Giovanni.'' Readers also benefit from detailed explanations of the mechanics of hearing for crickets (whose `` `ears' consist of thinnings on [their] front knees that vibrate only at certain frequencies made by rasping cricket legs''), various birds, dinosaurs, whales, as well as Jourdain's main focus, homo sapiens. He divides the book into chapters on the basics of sound and aspects of music (e.g., harmony and rhythm) and the ways we perceive them, then goes on to consider the neurological and emotional adaptations of composers and musicians to the demands of music, noting that there is no proof that any ``particular brand of emotionality is tied to musical greatness.'' Although the title implies that ecstasy is central to Jourdain's musical interest, this isn't addressed until the last chapter, which looks at music as a means of psychic healing and regeneration (``it lifts us from our frozen mental habits and makes our minds move in ways they ordinarily cannot''). Jourdain is an able guide in matters scientific. His comments on music as an art are less sophisticated. When discussing musical understanding, he remarks, `` `Meaning' is one of those fuzzy concepts that keep philosophers in business. It has no simple explanation.'' A know-it-all he isn't. But Jourdain knows enough to keep us listening.