In this paper, the author introduces the readers of Systems Practice to his biocybernetic approach to systems planning, an approach that he has shown to be fruitful both in concrete applications and in many best-selling didactic publications, including children’s books and games. Based on this approach he proposes a ‘cybernetic sensitivity model,’ a conceptual framework for ecologically sound systems design based on a biocybernetic redefinition of conventional techniques of systems modeling and simulation. The author explains the basic structure of the model and presents eight pertinent biocybernetic principles of good-systems practice.