This volume constitutes the proceedings of the third biennial conference of the International Society for Theoretical Psychology, held in Arnhem, the Netherlands, April 17-21, 1989. Fifty-six papers were presented during the four days of the conference, including an invited address by Professor A. D. de Groot, and seven papers composing two plenary sessions, four on the con tribution of history to theory, and three on theoretical alternatives for contem porary psychology. Of these, 46 papers are presented in the proceedings; all of which suffered editorial changes and, with the exception of...