Bibliometrics has moved well beyond the mere tracking of bibliographic citations. The web enables new ways to measure scholarly productivity and impact, making available tools and data that can reveal patterns of intellectual activity and impact that were previously invisible: mentions, acknowledgments, endorsements, downloads, recommendations, blog posts, tweets. This book describes recent theoretical and practical advances in metrics-based research, examining a variety of alternative metrics -- or "altmetrics" -- while also considering the ethical and cultural consequences of relying on...