This text is intended to contribute to an understanding of human behavior in the social environment by providing social work students with an introduction to American communities. The primary focus is on local communities of place. Attention is also given to the communities of interest and identification that are intertwined with geographic communities. Ecological systems and social systems perspectives serve as conceptual and practical frameworks for examining the multiple communities in which people have membership, social identity, and social interaction. This edition begins with an exposition of the societal context of communities. American society is recognized as part of a global community and then examined as a social system, a community of communities, a multicultural society, and a civil society. The book emphasizes the way that discrimination, economic deprivation, and oppression affect populations at risk and demonstrates the role communities play in the pursuit of individual and collective social and economic justice.