In this exploration of the health risks arising from the modern chemical revolution, concerned public-health specialist LappÇ (The Broken Code, 1985, etc.) reports not only on what the dangers are (they include agricultural pesticides, benzene in the workplace, chlorinated solvents in drinking water, ``nonreactive'' chemicals such as silicone in breast implants, and ``natural'' chemicals such as estrogens in contraceptive pills), but also on what we know; how we can know given the complexity of multiple exposure, cofactors, interactions, and delayed effects; and the policy implications of the findings he cites and the reasoning he applies. (Like Barry Commoner and others serious about the subject, LappÇ insists that control of the chemicals' production, not just their use and disposal, is essential.) Much of the book takes the form of an argument against those who would dismiss or deny the risks, as LappÇ devotes each of ten chapters to combating a particular ``myth'': that ``the body's defenses are adequate''; that ``naturally occurring substances cause most cancer''; that there is a ``safe threshold'' of toxicity, etc. He ends with a list of recommendations for hard-and-fast environmental regulations that would be hard to fault but gives no suggestions as to how to achieve them politically. There have been many books alerting the public to these dangers, yet the offenses continue. Still, LappÇ's knowledgeable critique of the pro-chemical arguments at least provides debating ammunition for serious nonscientists who share his concern and who can tolerate his far-from-punchy prose.