promotion, dispatch, taxation, finance, salaries etc., fit into this picture. Not all enterprises charge for their transactions (e.g. some schools and medical services, policing) and voluntary staff may not be paid. Advertising or shipping might not be part of the business or they might be the principal activity. Whatever the circumstances, all enterprises are required to be useful to their users if they are to remain viable. For all participants the central question remains: "Do I do what I always do for this transaction or do I innovate?" It is embodied in the calls on System 4. The VSM describes the constraints: a knowledge of past performance and how it may be improved. Beer dedicated Brain of the Firm to his colleagues past and present with the words "absolutum obsoletum" which he translated as "If it works it's out of date". See also American Society for Cybernetics Autonomous agency theory Business model Cybernetics Society Dynamic governance Project Cybersyn Viable system theory References Further reading 1959, Stafford Beer: Cybernetics and Management. The English Universities Press Ltd. 1972, Stafford Beer, Brain of the Firm; Allen Lane, The Penguin Press, London, Herder and Herder, USA. Translated into German, Italian, Swedish and French (The founding work) 1972, Stafford Beer, Managing modern complexity, in Landau, R., ed. 'Complexity', Architectural Design October 1972, pp. 629-632. 1974, Stafford Beer: Decision and Control. John Wiley & Sons, London and New York, 1975, Stafford Beer, Platform for Change; John Wiley, London and New York. (Lectures, talks and papers) 1979, Stafford Beer, The Heart of Enterprise; John Wiley, London and New York. (Discussion of VSM applied) 1985, Stafford Beer, Diagnosing the System for Organizations; John Wiley, London and New York. Translated into Italian and Japanese. (Handbook of organizational structure, design and fault diagnosis) 1989, Ed. Espejo and Harnden The Viable System Model; John Wiley, London and New York. 2007, William F. Christopher Holistic Management; John Wiley, London and New York. 2008, Türke, Ralf-Eckhard: Governance – Systemic Foundation and Framework (Contributions to Management Science, Physica of Springer, September 2008).Link 2008, Patrick Hoverstadt: The Fractal Organization: Creating sustainable organizations with the Viable System Model Wiley 2008, José Pérez Ríos, Diseño y diagnóstico de organizaciones viables: un enfoque sistémico, Universidad de Valladolid ReadOnTime 2010, Golinelli Gaetano M, "Viable Systems Approach (VSA): Governing business dynamics", CEDAM, Padova. 2010, George Hobbs and Rens Scheepers, "Cybernetics and the Agility Question," Proceedings of IFIP 8.2/Organizations and Society