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 the invited ad dress, were required to meet a 15 page restriction on length. The editors gratefully acknowledge John Mills, Leendert Mos, and Hank Starn for their invaluable editorial assistance. The papers included here are presented without discussants' commen taries. (Over 125 psychologists participated at the conference.) While the papers are representative of the scope of topics covered at the conference, the hours of formal and informal discussions must, unfortunately, be left to the reader's imagination. We encourage the reader to attend one of our next conferences, planned biennially, and alternately, in North America (1991) and Europe (1993)."