A concise overview of the warning system we call pain that includes the different types (acute, chronic, phantom, and referred), how we differ in our feelings about pain, how it's measured, how the nervous system sends us pain messages, and how we can effectively block those messages. There is also an up-to-date discussion of drugs, from aspirin to narcotics. Arnold's vocabulary occasionally turns overly technical for the targeted age group. Syllable sneezes are showered onto the pages--words like enkephalin, prostaglandins, and bradykinin. Readers will find some of their questions answered: Why injuries swell and how aspirin affects the system, for example. What they won't find is a drama that reaches out to grab them. A phenomenon such as the human capacity to turn off pain with acupuncture, hypnotism, and other means should be fascinating, almost miraculous. This is nearly lost in the scientific discussion. Still, a useful addition to a reference shelf.