2015 Reprint of 1958 Edition. Full facsimile of the original edition. Not reproduced with Optical Recognition Software. The Psychology of Interpersonal Relations pioneered the modern field of social cognition. A giant of social psychology, Heider had few students, but his book on social perception had many readers, and its impact continues into the 21st Century, having been cited over 13,000 times. In The Psychology of Interpersonal Relations, Heider argued that social perception follows many of the same rules of physical object perception, and that the organization found in object perception is also found in social perception. Because biases in object perception sometimes lead to errors (e.g., optical illusions), one might expect to find that biases in social perception likewise lead to errors (e.g., underestimating the role social factors and overestimating the effect of personality and attitudes on behavior). Heider also argued that perceptual organization follows the rule of psychological balance. Although tedious to spell out in completeness, the idea is that positive and negative sentiments need to be represented in ways that minimize ambivalence and maximize a simple, straightforward affective representation of the person. He writes To conceive of a person as having positive and negative traits requires a more sophisticated view; it requires a differentiation of the representation of the person into subparts that are of unlike value (1958, p. 182). But the most influential idea in The Psychology of Interpersonal Relations is the notion of how people see the causes of behavior, and the explanations they make for it-what Heider called attributions . Contents: Introduction -- Perceiving the other person -- The other person as perceiver -- The naive analysis of action -- Desire and pleasure -- Environmental effects -- Sentiment -- Ought and value -- Request and command -- Benefit and harm -- Reaction to the lot of the other person -- Conclusion -- Appendix: A notation for representing interpersonal relations.