Gunnar A. V. Borg was born in Stockholm on 28. November 1927. Educated at Stockholm University, he obtained his Ph. D. from the University of Lund in 1962. Subsequently he held various teaching and research appointments at the University of Umea in northern Sweden, where he also served as President of the Graduate School of Social Work and Public Administration in 1966-1967. In 1971 he was appointed Professor at Stockholm University, where he headed the Institute of Applied Psychology for over a decade. Since 1980 he has been at Stockholm University's Department of Psychology, and in 1987 he received a Professorship in Perception and Psychophysics. Over the last 20 years he has held several visiting appointments abroad, particularly in the USA, and has lectured at many universi­ ties both in and outside Europe. From the beginning of Gunnar's research career, his thinking has been affected by Gestalt psychology as well as by some principles of theoretical philosophy. The former has not only influenced Gunnar's early unconventional works on "gestalt strength" but also one of his major areas of thinking, the notion of "total perceived effort," which can be seen as a "gestalt" underlain by a variety of sensory data. The philosophical influence is obvious: Gunnar's papers reveal an abiding concern with epistemological issues, issues that are linked to his persistent attempts at making interindividual comparisons.