This special volume compares how different regions (countries or states) have attempted to reconcile the demands for polotical acceptability and economic efficiency in the design of markets for electric transmission. Each author addresses the same set of six criteria that policy makers consider important in designing transmission rules in a particular country. In this wasy, the papers collectively provide a structured international comparison of how buyers and sellers carry out transmission transaction in eight different countries or states.The idea of these papers arose from discussions within an ad hoc working group on electricity competition that was organized by the Energy Modleing Forum (EMF) at Stanford Uiversity. All authors participated in this study with other analysts and decision makers from business, government, and universities. The working group met 4 times between November 1995 and September 1997 to identify critical problems, design appropriate analysis, and develop supportable conclusions. As in past EMF studies, the purpose of this larger effort is to show how modeling and analysis can be used to improve one's understanding of important and fundamental energy problems.