Media studies focus on how everyday life and institutions, culture, and society change as people increasingly act and communicate with and in relation to media. This process is referred to as mediatisation, as communication occurs more frequently in media-mediated and mediatized forms. For empirical investigation, the concept of "social worlds" is utilized—various life domains such as work and family, entertainment and television, everyday life and social relationships, politics and learning are all affected, but in different ways. In the DFG-funded priority program "Mediatized Worlds," researchers from various disciplines have been examining these issues for several years. The present volume does not primarily present empirical findings.