Allan Kaprow examined his own concept of the artistic field of "happenings," and at the same time researched various works of the same trend and compiled them into a book. The result is "Assemblages, Environments, and Happenings". The book is a collection of art based on various acts from around the world, and includes photographs of them. The book includes Japanese artists such as Yayoi Kusama and Ay-O, but the specifics make up one chapter as a group. With this book, Gutai was greatly appreciated and introduced to the art world for the first time. However, although Kaprow covers Gutai as a pioneer, he does not break away from the Western-centered sense of art history.