This two volume Encyclopedia of Psychology is an International venture, both in the sense that the authors for the definitions and articles have been drawn from many different countries and also because it is being published in English, German, French, Spanish, Portuguese and Italian. Entries in this Encyclopedia are of two kinds. First there are the ordinary definitions, occupying a line or two, which can be found in most dictionaries; second, there are articles covering important terms and concepts, specially written by well known authorities, ranging in length up to 4,000 words, and containing suitable bibliographies for further study.