The picture book is a genus of children's literature. The definition and the history of the picture book are closely linked to the changing social ideas. Originally, the term was used for every book that was equipped with illustrations. Nowadays is usually including a specially designed book for children who can not yet read or are in the early ages of reading. The images occupy a leading role therein, although there is a strong correlation between image and text. The picture books are usually a small amount (usually up to 30 pages) and occur in all formats. The large-format book is the most commonly used form. Taking into account the age, the storybook is made often fibreboard, tear-resistant paper or foil.