The study is illustrative and theoretical in nature, as it was based on a review of the available literature on the subject (Polish and foreign). The publication is addressed to both scholars and students dealing with the subjects of population ageing, old age, and older adults, as well as to a growing group of practitioners interested in these issues, including politicians and decision-makers as well as representatives of public services, the media, and non-governmental organizations.

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Population ageing, total population growth, international migration and urbanization are four global demographic trends that are directly reflected in the functioning and directions of development at all organizational levels – from global and international, to from national to regional and local.
The identified changes in the age structure constitute a significant challenge for all societies. This is why this process is of particular interest to a variety of social, political, and scientific groups, which, through the public debate that has been going on for at least several decades, are trying to explain and respond to the observed changes. However, the interpretation of this increased attention can take on a strongly dichotomous character. This is because, on the one hand, thanks to the widespread interest in the ageing process, its descriptions gain an interdisciplinary, transdisciplinary, and multidisciplinary perspective. As a result, the ageing process ceases to keep secrets from us, and the accumulated knowledge grows, supplementing the existing image of this process with new, previously unknown faces. On the other hand, however, the fact that the ageing process remains the object of the increased interest of representatives of many scientific disciplines who use their conceptual apparatus results in the emergence of a multidimensional but not always a coherent image of the analysed fragments of social reality. This common interest contributes to a significant stratification of the definition and interpretation sphere used in descriptions and attempts to explain the issues raised.
Therefore, an essential task for the world of science is to properly delimit and configure (systematize) the accumulated knowledge, which should serve the development of the possibility of its application in practice. Hence, the idea to prepare the presented volume, the main research objective of which is to attempt to compile selected concepts, models, and theories functioning in the scientific circulation in the thematic area identified with the activity and activation of older people and the public policy towards of an ageing population. The study is illustrative and theoretical, as it is based on a literature review on the subject (Polish and foreign), a review of expert opinions and analyses prepared at the request of national and international institutions, as well as legal acts and other documents, the records of which turned out to be helpful in the conducted analyses.
The content of this volume corresponds to the three research questions posed. Firstly, by making a general description of the population ageing (pointing to its main determinants and the observed dynamics), an attempt has been made to identify the most critical consequences and challenges related to the observed changes in the age structure on a global scale and in individual societies. Secondly, efforts have been made to identify the fundamental differences in meaning and the resulting implications of using various concepts concerning the description and stimulation of activity, productivity, and social integration of people of immobile working age and older age. Thirdly, the focus has been placed on determining what the recommendations for public policy are with regard to population ageing due to the presence in the scientific and expert circulation of many interpretations of changes related to the emergence of post-industrial social policy. The structure of the presented study finally consists of parts – chapters – prepared in such a way that, on the one hand, they constitute a coherent set verifying and systematizing the concepts and interpretations of issues present in the literature, and on the other hand, they clearly show the reader, in line with the authors’ acceptance, one of the possible critical paths of analysis.
The first chapter is a kind of introduction to the discussed issues because its task is to familiarize the reader with the interpretations of basic concepts functioning in the literature, such as ageing, old age, and longevity, but also to serve as a reference to the category of immobile people in working age or older people in the perspective of the life cycle. The theoretical, conceptual framework identified in this way, associated with the population ageing process, was supplemented with the presentation of demographic data aggregated at various levels of generality, which refer to selected indicators and measures used in the statistical analysis of the process discussed. In this way, the desired effect of multidimensionality has been obtained, both in terms of theoretical considerations and in terms of the presentation of statistical distribution reflecting the specificity of the dynamics of the ageing visible in the European Union (EU) and Poland.
The second chapter is entirely focused on defining the concepts of activity, activation, productivity, as well as social and professional integration of people in the age of immobility and older adults. Therefore, the reader will find in it a critical literature review, which also gives a chance to receive information about the connections between the issues mentioned. Their significant supplementation is also a reference to the concept of productivity of older people and the observed interpretation changes of this issue, manifested in the qualitative expansion of the thematic planes that make up its conceptual framework.
In the third chapter, the authors attempt to present the differentiation of the concept of public policy on ageing. Therefore, the reader can become familiar with the interpretations of the impact of demographic changes and other conditions on post-industrial social policy present in the literature on the subject. So, here the authors focus, among others, on the concepts of active, coherent, and investment social policy implemented in the context of the ageing process, but also references to selected concepts of stimulating social and professional activation of people in immobile age and older adults. This is primarily about the social aspect of productivity, the analyses of which, especially at the beginning of the 21st century, contributed to a kind of restitution, an almost forgotten concept of co-production. Relating the conceptual considerations in the literature concerning this phenomenon occurring and developing within public services to the issue of the population ageing, the authors also present a silver (senior) adaptation of co-production. The whole publication concludes with an analysis of the concept of preparation for longevity and the potential application of behavioral economics tools in public policy on longevity.
The publication is addressed both to scientists and students focused on the topic of population ageing, old age, and older people, as well as to a growing group of practitioners interested in these issues, including politicians and decision-makers, representatives of public services, representatives of the media and non-governmental organizations. The authors hope that the presented results of the conducted query will prove helpful for the reader both in defining the conceptual framework of the issues under consideration and in attempts to adapt and implement the assumptions of the concepts cited in the realities of the social life of specific communities. Thus, the added value of the presented volume will be the systemic valorization of old age, which-similarly to the earlier phases in human life-should serve further development and self-realization.