In the history of any scientific discipline, certain people stand out because they effectively defined the discipline, separated it from neighbouring specialities, and gave it a local habitation and a name. Three names stand out in the history (brief though it may be) of the scientific study of personality. The first is A. Heymans, a Dutch philosopher who almost single-handedly introduced the various theoretical, methodological and psychometric methods that characterise modern personality study (Eysenck, 1992). In the early years of this century, he put forward theories of specific personality dimensions, carried out rating studies on large numbers of subjects, correlated traits and devised a primitive method of factor analysis, derived factors that have stood the test of time (extraversion and neuroticism, to give them their modern names), and even went so far as to carry out psychological and physiological experiments to test deductions from these theories. As a reward for all this pioneering effort he is completely neglected in the modern literature; Hall et al (1985), in their Introduction to Theories of Personality gave much room to nonentities like Medard Boss, but make no mention of Heymans. He committed the ultimate crime of not being born in America, and must therefore be considered a non-person. Fortunately his theories and methodologies five on, largely in the London School.