Book excerpt: The demographic phenomena of increased life expectancy, increasing global population of older adults, and a larger number of older people as a proportion of the total population in nations throughout the world will affect our lives and the life of each person we know. The changes will result in challenges and benefits for societies and people of all ages. These events need to be understood, explained, and their consequences addressed; sociological theories about aging are an essential part of this process. In Understanding Aging and Diversity: Theories and Concepts, Patricia Kolb presents important sociological theories and concepts for understanding experiences of older people and their families in a rapidly changing world. She explores concepts from phenomenology, critical theory, feminist theory, life course theory and gerotranscendence theory to explain important issues in the lives of older people. This book investigates similarities and differences in aging experiences, focusing in particular on the effects of inequality. Kolb examines the relationship of ethnicity, race, gender, sexual orientation and social class to international aging experiences. This book explores the relationships between older people and social systems in different ways, and informs thinking about policy development and other strategies for enhancing the wellbeing of older adults. It will be useful for students and scholars of sociology, gerontology, social work, anthropology, economics, demography and global studies.