Book excerpt: The continuous growth of older populations, as a consequence of demographic changes, is a huge global challenge. The growing proportion of older adults not only burdens the healthcare system, specifically, in developing countries but also posits a challenge at the household level, specifically, in nuclear and one-person households. For societies as a whole to avoid costly and negative effects, it is crucial to increase their knowledge of how to promote good health among older adults, so that they can live longer and enjoy a better quality of life. Active aging is the process of optimizing opportunities for health, participation, and security in order to enhance quality of life as people age. An active and healthy life has remained one of the most important aspirations for all people, both young and older adults alike. This ambition has become a genuine possibility for many due to a rising life expectancy among people of diverse attributes across the world. While celebrating longer life and more financial security in later life than ever before, we need to challenge how these aspirations can be sustained, through our own behavioral responses and through public policy, institutional reforms, and innovations. The challenge is to identify, recommend, and promote strategies and interventions that stimulate and sustain the activity, independence, and health of people of all ages, especially older adults, and, in the process, promote the well-being and quality of life of people and make public welfare systems more sustainable.