"Bowling Alone" is a book by sociologist Robert D. Putnam that explores the decline of social capital in the United States. Putnam argues that people are increasingly disconnected from family, friends, and community organizations, leading to a decrease in civic engagement and social trust. He uses the metaphor of bowling to illustrate this trend, noting that while more people are bowling, they often do so alone rather than in leagues. The book highlights various factors contributing to this decline, including changes in technology, increased mobility, and shifts in work patterns. Putnam emphasizes the importance of social connections for individual well-being and the health of democracy, urging a revival of community involvement and collective activities.