In the year 2022, the fourth review and appraisal of the Madrid International Plan of Action on Ageing (MIPAA) are taking place. It is worth reminding that “building a society for all ages” is a key challenge of this United Nations strategic document. However, nearly 20 years after the adoption of MIPAA, the studies on intergenerational relationships are still not adequately advanced. At the same time, the list of relevant topics that needs more in-depth studies is growing. Examples include intergenerational issues in population theories and population projections; intergenerational family relations and social support; intergenerational relations in the context of population ageing, migrations, longevity, and depopulation; intergenerational solidarity in social security and welfare state institutions; intergenerational challenges in the socio-economic and environmental changes including achieving the Sustainable Development Goals; intergenerational programs and policies; and age-friendly environments, cities, and communities.