PRINCIPLES OF TOPOLOGICAL PSYCHOLOGY by KURT LEWIN. Originally published in 1936. PREFACE by DR. WOLFGANG KOHLER Swarthmore College Swarthmore: DEAR KOHLER This book is the result of a very slow growth. I remember the moment when more than ten years ago it occurred to me that the figures on the blackboard which were to illustrate some problems for a group in psychology might after all be not merely illustrations but representations of real concepts....