American science fiction has been a significant source of ideas and imagination for Japanese creators: they have been producing extensive works of not only written texts but also numerous films, television shows, Japanese comics and cartoons (Manga and Animé), music, and other forms of art and entertainment under its influence. Tracing the history of the import of American science fiction works shows how Japan accepted, consumed, and altered them to create their own mode of science fiction, which now constitutes the core of so-called “Cool-Japan” content. Popular American science fiction emerged from pulp magazines and paperbacks in the early 20th century. In the 1940s, John W. Campbell Jr. and his magazine Astounding Science Fiction had great impact on the genre, propelling its “Golden Age.” In the 1960s, however, American science fiction seemed dated, but the “New Wave” arose in the United Kingdom, which soon affected American writers. With the cyberpunk movement in the 1980s, science fiction became part of postmodernist culture. Japanese science fiction has developed under the influence of American science fiction, especially after WWII. Paperbacks and magazines discarded by American soldiers were handed down to Japanese readers. Many would later become science fiction writers, translators, or editors. Japanese science fiction has mainly followed the line of Golden Age science fiction, which speculates on how science and technology affect the social and human conditions, whereas the New Wave and cyberpunk movements contributed to Japanese postmodernism. Japanese Manga, Animé, and special effects (SFX) television shows and films (Tokusatsu) are also closely related to science fiction and have developed under its influence. Even as works of the Japanese popular culture owe much to American science fiction, they have become popular worldwide.