Titles on social media and libraries are abundant, but most focus on marketing and outreach. Young and Rossman take a slightly different approach—using social media to foster conversations and build communities. In three distinct sections (developing communities of users, creating communities of professionals, and transforming communities into action for social justice), the editors highlight voices from a range of library types—public, four- and two-year college, health sciences, and school libraries, as well as archives. While each chapter presents valuable information, this book makes its mark with its final section. Here, Jarrett M. Drake examines how Princeton University documented its students’ #OccupyNassau movement, and April M. Hathcock discusses relying on Twitter to spark discussions of critical librarianship.... Verdict: This selection will be helpful to librarians and staff considering delving into social media, as well as those looking to harness it in new ways.