Critical thinking is a major goal of social studies education. Teachers need to know what critical thinking is before they can successfully incorporate the skill into their teaching strategies. Understanding why critical thinking is a major goal of education in a free society helps teachers prepare students to be informed and rational participants in civic affairs and to gather enduring intellectual abilities to make themselves more effective as students. To develop skills for critical thinking requires that teachers ask challenging questions and require students to provide evidence for their answers or opinions. Encouraging students to examine different positions on controversial topics in an open supportive classroom environment prepares them for the responsibilities of participating in a free society. Included in this document are nine related references. (JEH)