How is one to evaluate warnings of risk from the introduction and use of new technologies? Examining 31 cases of human health warnings raised in the 1950s and 1960s about such technologies as fluoridation, DDT, cyclamate, nuclear weapons testing, and birth-control pills, Mazur (public affairs, Syracuse U.) tests four hypotheses about the validity of warnings: true warnings are more likely to come from conventional scientific channels and sources, false alarms are more likely to have sponsors with biases against the producer of the alleged hazard, "hyped" media coverage is more likely to indicate false alarms, and "derivative" warnings arising from popular social issues are more likely to indicate false alarms. Annotation ©2004 Book News, Inc., Portland, OR (booknews.com)