Book excerpt: This book offers a comprehensive investigation of the ways in which social media has affected change to the constitution of mainstream journalism. The volume does this in a unique way – by tracing the links between the different changes social media has brought to individual journalism practice, organisational processes and policies and institutional understandings of journalism. The role of social media platforms in the changing professional landscape of journalism is explored, both in terms of the changes that social media platforms have impacted on journalism, but also the way in which journalistic use of social media has impacted on particular uses of these platforms. Therefore, Journalism and Social Media is not simply a description of changed journalistic practices, but endeavours to encapsulate a complex and integrated techno-social relationship, incorporating both the individual practices of journalists, as well as the larger organisational and institutional changes that have occurred due to the increasing use of social media to investigate, present and disseminate news.