Coloring books are * Educational
Paint books and coloring books appeared in the United States. The McLoughlin brothers are credited as the inventors of the coloring book, when, in the 1880s, they produced The Little Folks' Painting Book, in collaboration with Kate Greenaway. They continued to publish coloring books until the 1920s, when the McLoughlin Brothers became part of the Milton Bradley Company.
Until the 1930s, books were designed with the intent for them to be painted instead of colored. Even when crayons came into wide use in the 1930s, books were still designed so that they could be painted or colored. Source: Wikipedia.