The applications of mathematics in the development of sampling methods are generally well known and appreciated. However, mathematics is now engaged in other problem-solving roles which will be just as important to marketers in the future as sampling is and was in the past. Already, powerful analytic devices such as Markov Chains, Mathematical Models, Simulation Techniques, Monte Carlo Methods, and other techniques have been applied to marketing decision making. It is the purpose of this series of bulletins to present at occasional intervals non-mathematical expositions of some of these applications. The first Bulletin will be concerned with a discussion of Markov Chains.