This volume presents a detailed and comprehensive treatment of mathematical models of attitude change, in which verbal theory is translated into families of mathematical attitude change models. The models so presented address three areas: 1) existing verbal attitude change theories which are translated into families of mathematical models; 2) attitude change theories that have been previously quantified are critiqued, and alternative mathematical models are given; 3) new theory and corresponding mathematical models are offered. Models of source change--change in the attitude toward the source of information are also addressed. For nearly every attitude change model discussed, corresponding models for change in attitude toward the source of information are also given. This volume explicitly considers two types of attitude change: attitude toward the object of the message (attitude change) and attitude toward the source of the message (source change). In keeping with the development and use of these models, examples are drawn from multiple disciplines and embrace a variety of approaches to the general study of communication, cognition, and change.