Franklin is a journalist who grabs the reader by the lapels. Such style (along with some pretty good tales) led to two Pulitzer Prizes. Now, he has chosen to flesh out to book length the second of the award-winning series, originally called ""The Mind-Fixers.' And a lot of Gee Whiz there is, plus much posturing on what it all means. First things first. The science Franklin writes about is the discovery that nerve cells talk to each other chemically. The first discoveries came by chance: a neurosurgeon found that an antihistamine called chlorpromazine calmed patients before surgery--and later that is also quieted the voices that schizophrenic patients heard. Then there was iproniazid, an anti-tubercular drug that soon had the patients dancing in the aisles. Reserpine, on the other hand, an ancient drug that lowered blood pressure, had just the opposite effect: it made some people wretchedly depressed. It didn't take long before neurochemists developed techniques to create ""wet"" maps of the brain--fancy radioactive tracers and scanners that could pinpoint which cells had receptors for certain molecules and which nerve endings juiced them with the magic fix. The rest continues to make history--in the form of transmitters like the endorphins--man's natural painkillers--and assorted sites and cells that answer the call of valium, or alcohol or PCP. A lot of the writing', here is lively and makes good if occasionally flawed sense. (Take Franklin's soundings on some genetic theories of hypochondriasis, of pain, alcoholism, and criminality, with some salt.) On the other hand, he quickly points to the dangers of labeling people or the moral dilemmas that genetic tests can create. Finally, Franklin assumes that everyone shares his ambivalence about giving up a spiritual mind for a molecular psychology (""the most inhuman of all approaches to the human condition""), and he seems enormously grateful that one eminent neurochemist says of course she believes in God! Stuff and nonsense sours what might have been a pretty palatable stew.