Over time and across Western democracies, the media has become increasingly influential, and a great deal more political processes have become altered, shaped or structured by the media and the perceived need of individuals, organizations and social systems to communicate with or through the media. The key theoretical perspective to understand this process is mediatization. As a long-term process which has increased the importance of the media and their spill-over effects on political processes, institutions, organizations and actors, mediatization is one of the most important processes reshaping politics and transforming democracies across the Western world.While the theoretical perspective of mediatization has become increasingly popular in recent years, scholarly understanding of the mediatization process and its antecedents, consequences and contingencies are still hampered by unresolved questions and a lack of systematic empirical studies. This volume addresses this by bringing together contributions that analyze and investigate different facets of the mediatization of politics, making a significant contribution to our theoretical as well as empirical understanding of this process, and setting the agenda for further research.This book was originally published as two special issues, of Journalism Studies and Journalism Practice.