This booklet is part of a series designed to help students take and defend a position on public issues. This booklet addresses the issues faced by society and individuals due to advances in scientific knowledge. It presents questions, stories, and scenarios for student discussion. Students are instructed to identify three kinds of questions in a discussion: (1) ethical or value questions; (2) questions of definition; and (3) questions involving facts and explanation. The document consists of six sections. The first is an overview that introduces the series, explains to students what the issues to be examined are, and suggests how the student should approach these issues. The second section deals with society and the limits that it places on science. As illustrations of the power of society to repress scientific knowledge, this section discusses the trial of Galileo and the modern example of the cancellation of funding for a conference on possible links between genetics and violence. The third section describes the dilemma faced by scientists when society disapproves of or condemns as evil their methods or studies. The next section is on specialized knowledge and decision making. It presents scenarios of debates over the fluoridation of water and how much information physicians may withhold from patients or their families. The fifth section relates these issues to current topics and choices about creating and using knowledge. The final section presents questions for review and discusses the issue of choices and of who funds what research. The accompanying teacher's guide focuses on the following organizing questions: (1) Under what conditions, if any, would it be in the public interest to prohibit or limit certain lines of investigation, to keep investigations secret, or to prevent a person from disseminating a scientific belief? (2) Under what conditions, if any, might a scientist's obligations to her profession conflict with obligations to her country or to humanity? How should these dilemmas be resolved? and (3) What is the citizen's obligation to understand science? What kinds of public policy questions should citizens delegate to scientists and experts? The guide breaks down teaching the unit into preparation, introduction of the unit, and a basic discussion of each section of the unit. A 6-item bibliography and handouts are included. (DK)