Koffka (1935) presented the law of Prägnanz as the main principle to guide research on perceptual organization. This law states that psychological organization will always be as “good” as the prevailing conditions allow: we will always organize our visual input in the best way possible. However, what does it mean for a psychological organization to be “good” or “prägnant”, and what are the prevailing conditions to take into account? Notwithstanding the abundant reference to Prägnanz in many journal article introductions and discussion sections since its emergence, the concept has remained very vaguely defined. In addition, the original Gestalt psychological context in which Prägnanz originated got lost, and the interpretation of Prägnanz has changed together with the shifting theoretical context (i.e., increasing focus on information processing theories). What does Prägnanz mean, and why should we care? In this talk, Eline Van Geert will review different aspects of the Prägnanz concept, and motivate why pursuing a clearer and more nuanced definition of Prägnanz is relevant for perception science, even – or especially – today. In addition, she will highlight the close historical connections of Prägnanz to the understanding of human aesthetic appreciation.