A description is provided of the use of a Critical Thinking Worksheet as a pedagogical tool for introducing critical thinking to students of philosophy and informal logic. First, an accompanying handout introduces essential terms such as "argument,""conclusion," and "reasons or premises." The worksheet itself constitutes the second page of the handout. It begins by asking students to identify the premises and conclusion in a brief paragraph on smoking, and then guides discussion through the steps in the process of critical thinking, covering ambiguous terms, the truth of the premises, the strength of the argument, the use of emotive tone, the fallacies in the argument, counterarguments, a summary assessment, additional information needed, response to counterarguments, and the student's own view. Additional handouts provide students with assistance in verifying the truth or falsity of the premises of an argument and in identifying kinds of fallacies, such as hasty generalizations, false causes, argument resting solely upon the strength of an authority, argument against the person making the claim rather than the claim itself, and appeals to emotion. After using the worksheet with the smoking argument, students are asked to write on a new topic and provide their own examples. The use of the worksheet has resulted in radical improvements in student papers. (LAL)