Ludwig von Bertalanffy's theory of laws is applicable to virtually every scientific field. This conceptual approach has had a profound impact on biology, economics, psychology, and demography, with new relevancies today. Gathered here are Ludwig von Bertalanffy's writings on general system theory, selected and edited to show the evolution of systems theory and to present its applications to problem-solving. The new foreword by University of Vienna system theory professor, Wolfgang Hofkirchner, and Centre for Systems Philosophy director, David Rousseau, discusses the theory s contemporary applications.