The Cutting Edge of Modern Mathematics, Unveiled by "Arrows" Category theory, arguably one of the most important fields in modern mathematics. Its high degree of abstraction and generality is demonstrating its rich power in all areas, including physics, computer science, biology, linguistics, and aesthetics. This special feature will introduce and examine the basics of category theory, its various applications, and even its philosophical implications, in order to get to the heart of this increasingly prominent mathematical way of thinking. [Discussion] Fumihito Kato + Koya Saigo [Essays] Eiji Aratake / Satoshi Ito / Takeo Uramoto / Mariko Obara / Akihiro Kubota / Yukio Gunji Pegio / Kazutaka Kondo / Shigeru Taguchi / Shogo Tanimura / Daisuke Nakamura / Dai Tamaki / Taichi Haruna / Masayuki Hiyama / Masashi Funano / Yoshihiro Maruyama / Hiroyuki Miyoshi…