This book provides an overview of the system of ideas of this important and difficult author and explains his terminology in a manner which is easy understandable. The »Einführung» (Introduction) is the result of a long-term study of Bion‹s (1897–1979) ideas and of conversations between the three authors and Bion himself. After its first publication in Spanish in 1973, the work soon received international attention and was translated into many languages. This is a revised and extended edition in German.