Wolfgang Kohler's two latest books deserve the attention of phenomenologists for several reasons. Relations between Gestalt psychology and phenomenology have always been friendly, if not very well developed. As far as they have met on psychological ground, the two schools have worked along parallel lines and largely with concordant results. Christian von Ehrenfels' "Gestaltqualitäten" had their equivalent in Edmund Husserl's "figurale Momente" or "Einheitsmomente."² Gestalt psychology proper, fighting both against behaviorism and against a prejudiced introspectionism, which attempted to reduce all phenomena to pure sensory elements, has energetically upheld the part of unadulterated immediate experience.³ By the use of phenomenology in the sense of descriptive psychology, as it had been developed in psychology long before phenomenology as a philosophical movement had been started, Gestalt psychology has investigated a large group of hitherto neglected phenomena, notably those designated by the term "Gestalt." But in addition to that, by stressing the part of "insight" in mental processes, it has come close to the phenomenological concept of insight into essences ("Wesenseinsicht") and has moreover demonstrated its significance for actual thinking and for other psychological problems.