MARKETS <i> by Martin Mayer (W.W. Norton: $18.95) </i>

This book, subtitled “Who Plays, Who Risks, Who Gains, Who Loses,” is not a guide to investing. It is a personal tour of the world’s financial markets; it explains how markets work and who works them. With 24 books to his name, of which about half are on financial subjects, Martin Mayer expertly knits together explanations, details and theories about prices and what determines them, about traders and what it is they trade. From a bird’s-eye view, he can zoom in to show the reader a piece of the puzzle--say, a fish auction in Massachusetts--then swoop out again to demonstrate the significance of the detail in the global picture.

Last fall’s market crash cut short Mayer’s research for the book and added to the urgency of some questions involved in the work. Mayer asks, for example: Are there mechanisms built into the system that have made the world’s financial markets unstable and dangerous for all but the big brokerage houses? “Oct. 19 should have chilled fantasies,” Mayer warns. “It did, but only briefly. The losses have been taken but not internalized. The denials persist.”