Since its formation as a girl group in 2005, AKB48 has become a phenomenal success and institution in Japan. Having originally recruited fans with photocopied fliers and daily performances in the Akihabara area of Tokyo, AKB48 now saturates Japan. Its members--nearly 800 of them, including five sister groups and four so-called "rival groups" across Japan, as well as six sister groups in other Asian cities--appear in print, broadcast, online, and social media; in advertisements and on products; at home and on the train; on- and off-screen. AKB48's multi-platform omnipresence is characteristic of "idols," whose intimate relationship to fans and appeals to them for support have made the group dominant on the Oricon Yearly Singles Chart in the 2010s; they hold several records, including most consecutive million-selling singles sold in Japan. A unique business model relentlessly monetizes fans' affections through meet-and-greet events and elections, which maximize CD sales, and their saturated presence in the media. At a time when affect is more important than ever in economic, political, and social theory, this book explores the intersection of idols and affect in contemporary Japan and beyond.