Drawing on research from multiple disciplines and international case studies, this book provides a comprehensive and up-to-date understanding of online disinformation and its potential countermeasures. Disinformation and Manipulation in Digital Media presents a model of the disinformation process which incorporates four cross-cutting dimensions or themes: bad actors, platforms, audiences, and countermeasures. The dynamics of each dimension are analysed alongside a diverse range of international case studies drawn from different information domains including politics, health, and society. In elucidating the interrelationship between the four dimensions of online disinformation and their manifestation in different international contexts, the book demonstrates that online disinformation is a complex problem with multiple, overlapping causes and no easy solutions. The book's conclusion contextualises the problem of disinformation within broader social and political trends and discusses the relevance of radical innovations in democratic participation to counteract the post-truth environment. This up-to-date and thorough analysis of the disinformation landscape will be of interest to students and scholars in the fields of journalism, communications, politics, and policy as well as policymakers, technologists, and media practitioners. This research received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 825227.