Shōnen Book was a manga magazine by Shueisha, which debuted March 1958 and ended in April 1969. Shōnen Book was originally a spin-off of Shueisha's Omoshiro Book . Shōnen Book is famously known in Japan for being the predecessor to the company's famous Weekly Shōnen Jump magazine. The Shōnen Book tankōbon manga volumes are published under the Shōnen Speed Ō (少年スピード王) manga imprint. Shōnen Book was a part of Shueisha's former leading magazine line, Book, now Jump. Shōnen Book was created in 1958 as a male version of the short lived Shōjo Book. Omoshiro Book became an offshoot of the magazine, and eventually faded away in the middle of the Shōnen Book timeline. Shōnen Book also served as a root to many other magazines published by Shueisha.

Shueisha Inc. is a Japanese publishing company headquartered in Chiyoda, Tokyo, Japan. Shueisha is the largest publishing company in Japan. It was established in 1925 as the entertainment-related publishing division of Japanese publisher Shogakukan. The following year, Shueisha became a separate, independent company.