"Banal and familiar to its users but complex and ambiguous in its impact, WhatsApp's closed doors make it harder to study than the darlings of digital platform research, Facebook and X. Undeterred, the authors of this volume make sense of its multiple ambivalences: how, for example, WhatsApp affords users private spaces while also serving as a channel for the broadcast of organised hate propaganda. This book represents a quantum leap in scholarly knowledge about of one the world's most engaging communication platforms and the human networks it activates." (Cherian George, author of Fighting Polarisation) "Two leading scholars of media, journalism, and disinformation have gathered a comprehensive collection of chapters that shed light on issues of burning importance globally. Their treatment of extremism, freedom of speech, and disinformation issues as they become manifest in the use of the universally popular WhatsApp is an undoubtedly original contribution to our understanding of the global struggle in which truth is assaulted from all sides. This volume is poised to become a classic reference for years to come, and a valuable tool in teaching and research." (Marwan M. Kraidy, Northwestern University)