Gr 7 Up-- An extensive factual account of these dangerous substances with an emphasis on the biological basis of drug dependency. The text focuses on different forms of cocaine and explains why crack is potentially the most deadly variety yet to appear. The authors seek to explain many myths about cocaine use. Their comprehensive discussion of the physical and psychological aspects of cocaine addiction leave little doubt that even the most casual use of the drug puts users at grave risk. One chapter offers fictionalized case studies of troubled individuals and suggests both sources and methods of getting help. A final chapter, devoted to the prevention of the spread of cocaine abuse, is followed by a list of sources of further information, as well as a useful glossary and excellent bibliography. Although readable, Cocaine and Crack contains more technical detail than some other current books on this topic. Diagrams, which are generally well done, explain some of the more difficult concepts. More suitable for reports than self-help, Cocaine and Crack will be a serviceable addition to junior and senior high collections. --Sue A. Norkeliunas, Arlington Senior High School, LaGrangeville, N.Y.