A remarkably evenhanded look at a charged subject. Since its discovery by Lindenmann in 1957, the drug interferon has been alternately exalted and discredited in the search for cures for cancer, viral diseases, and the common cold. The substance is ""a sinuous, sticky protein"" found in most higher animals and virtually all human cells that seems to have ""startling capabilities"" against viruses. But researchers have had trouble studying interferon, Edelhart found, because of the very limited supply (blood from 270 donors is needed to produce interferon to treat one person for a few weeks)--and the resulting astronomical cost. Controlled trials have therefore been impossible. Edelhart provides a clear, accurate explanation of how the drug was discovered, what is known about how it works, how it has affected the few who've been treated with it, and what it may eventually be used for (genetic engineers are much interested). But what he describes equally well is the struggle over interferon within the cancer-care industry: i.e., the medical people, the major cancer research centers, and the American Cancer Society. As a chief researcher at Sloan Kettering describes it, the A.C.S. decided to back interferon testing because ""the time was ripe for a dramatic, provocative leap forward in cancer research--something totally different for the cancer establishment to use as a counterweight to laetrile and other specious cures."" Edelhart looks objectively and knowledgeably at interferon's status, and puts it back in perspective for us.