Increased attention should be given to the expression of deductive arguments in high school geometry, according to the Curriculum and Evaluation Standards for School Mathematics (NCTM 1989). In general, the standards for grades 9-12 emphasize helping students develop their logical-reasoning skills. One means by which high school geometry textbooks typically introduce the notion of deductive reasoning and the principles oflogic is by examining conditional statements and their converses, inverses, and contrapositives. This article describes an episode involving conditional statements and the notion oflogical equivalence that occurred in a tenth-grade college-preparatorygeometry class. The episode illustrates some of the confusion that can arise in connection with this topic for both students and teachers. The ensuing discussion