Tarō Hirai (平井 太郎 Hirai Tarō, October 21, 1894 – July 28, 1965), better known by the pseudonym Edogawa Ranpo (江戸川 乱歩), also romanized as Edogawa Rampo, was a Japanese author and critic who played a major role in the development of Japanese mystery fiction. Many of his novels involve the detective hero Kogoro Akechi, who in later books was the leader of a group of boy detectives known as the "Boy Detectives Club" (少年探偵団 Shōnen tantei dan).

Ranpo was an admirer of Western mystery writers, and especially of Edgar Allan Poe. His pen name is a rendering of Poe's name. Other authors who were special influences on him were Sir Arthur Conan Doyle, whom he attempted to translate into Japanese during his days as a student at Waseda University, and the Japanese mystery writer Ruikō Kuroiwa.