Because of advances in public health and medicine, increasing longevity is the trend in all regions of the world. Families, communities, and governments are taking on the promises and challenges of population aging as more people in every society enter the ranks of later life. The nature of opportunities, problems, and solutions depends heavily on economic and cultural foundations of the society. Longer working lives, the viability of pensions, family caregiving, the need for education about aging, and lifelong community involvement are examples of the aging-based changes that can affect individuals, their families, and their communities. This chapter describes demographic aspects of population aging, the implications of this unprecedented set of changes, and some societal responses. It presents the process of global aging research uses studies on happiness among older adults to illustrate the ways in which comparative data helps to identify the uniquenesses and commonalities of the aging experience.