Since its formation as a girl group with 20 members in 2005, AKB48 has become a phenomenal success and institution in Japan. Having originally recruited fans by handing out photocopied fliers on the street and performing daily in a dedicated theater in the Akihabara area of Tokyo, AKB48 now saturates Japan. Its members--nearly 800 of them, including five additional sister groups and four so-called "rival groups" in locations across Japan as well as six sister groups in major Asian cities overseas - appear in print, broadcast, online, and social media; in advertisements and on products; at home and on the train; on- and off-screen. Such multi-platform omnipresence is characteristic of the "idol," a heavily produced and promoted performer who is in intimate relation to fans and appeals to them for support. And AKB48's appeals have astonishing results. From 2010 to 2018, the group's singles have occupied the top two to five spots of the Oricon Yearly Singles Chart, and almost all sold over a million copies. They hold the record for most singles sold by a female artist or group, highest Japanese sales of a single by a female artist or group, most consecutive million-selling singles sold in Japan, most million-selling singles in Japan, and more. 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.