Successful Ageing A Survey of the Most Important Theories The issues of good and successful ageing are the subject of scientific research. Successful ageing is the attempt to achieve a state of inner satisfaction and happiness in spite of the negative effects associated with old age: loss, external and internal destabilization, etc. Successful development in old age has many forms. It can generally be defined as an attempt to achieve the greatest profit with the smallest loss. The problem is establishing the universal criteria of successful ageing. It is possible to restrict the study to the observation of individual factors which are either objective or subjective, long-term or short-term, specific or universal or static versus dynamic. The problem is creating a theory that will explain all the processes and consequences of old age—none of the theories has so far succeeded in doing this. Life satisfaction as a subjective criterion of successful ageing has been most emphasized in two contradictory theories: activity theory and disengagement theory. Other theories are: growth theories, cognitive theories, dynamic theories, SOC model, cultural anthropological theories, the interaction model of longevity, etc.