It is rare for the political scientist who handles data which he has not generated himself to cast his mind to that of an observer watching an experiment, it is equally rare for him to plan controlled experiments in which he creates his own data.This lack of attention to the experimental aspect of political science hinders the development of the discipline, especially in relation to the building and testing of adequate theories.To remedy this lack a Round Table conference of the International Political Science Association was held in Vancouver in March 1970. The papers presented at the conference are published in this volume. They discuss the application of experimental techniques to the study of politics and give examples of such applications ranging from paper and computer games to experiments involving the observation of human interaction in a laboratory or in the field. It is hoped that this work will lead to a greater use of controlled experiments in a discipline which has not yet given to the experimental method the importance it should have in the production of relevant data and in the building and testing of theories.