The need to develop connections between members of different generations is being driven by a host of trends and challenges, including demographic shifts, workforce shortages and multigenerational teams, educational gaps, caregiving demands, youth and senior health and housing problems, economic insecurity, and rapid technological change. Many of these trends and challenges, already under way, were accelerated or exacerbated by the COVID-19 pandemic. This handbook presents what is known about the spectrum of intergenerational initiatives in the United States and abroad—the very first to do so in reference book form. It addresses specifically what increases cooperation, interaction, or exchange between any two (or more) generations and how to foster the sharing of skills, knowledge, or experience between old and young. Comprising 30 chapters, each written by leading experts in their field, the handbook is organized around five sections: Cross-Generational Relationships, Older Adults Working with Younger People, Younger People Helping Older Adults, Global Perspectives on Intergenerational Relationships, and Recommendations for Strengthening and Sustaining the Intergenerational Movement.