any type of picture or decoration used in conjunction with a text to embellish its appearance or to clarify its meaning. Illustration is as old as writing, with both originating in the pictograph. With the advent of printing, the art of hand-painted illumination declined as a means of book illustration.
Modern book illustration originated in the 15th-century block books, in which the text and the illustration were cut on the same block. Book illustration has followed closely the development of the printing processes. Copperplate engraving and etching tended to replace the woodcut during the 16th and 17th cent., but it was not until the close of the 18th cent. that the art was revolutionized by Thomas Bewick's ingenious use of wood engraving and Senefelder's invention of lithography. These two processes greatly stimulated the production of illustrated books and magazines and were exploited by such masters as Daumier, Doré, and Gavarni.
In the late 19th cent. wood engraving and lithography were superseded by the photomechanical processes that made possible the reproduction of a wide variety of painting and drawing techniques. The exploitation of these processes for cheap and rapid but sloppy mass production obscured their artistic potential. Thus early hand processes were revived in book illustration by such artists as William Morris, Matisse, Rouault, Picasso, Chagall, Rockwell Kent, and many others. However, such major illustrators as Aubrey Beardsley, Howard Pyle, and Elihu Vedder understood and exploited the photomechanical processes to great effect in the reproduction of their art works. Other great artists famous for illustration are Dürer, Holbein, William Hogarth, William Blake, Manet, and Winslow Homer.
Illustration of fiction was more popular in the 19th cent. than in the 20th. Dickens's works were illustrated by John Leech, H. K. Browne (“Phiz”), and George Cruikshank. Sir John Tenniel's illustrations for Alice's Adventures in Wonderland are almost as well known as the text itself. Today much of the finest illustration is done in the field of children's literature. From Beatrix Potter to Ludwig Bemelmans and Maurice Sendak, a number of gifted writers of children's stories have illustrated their own books. Among the great illustrators of children's books are Kate Greenaway, Walter Crane, Randolph Caldecott, Edward Lear, Ernest Shepherd, Palmer Cox, A. B. Frost, and Wanda Gág (see children's book illustration).
In the Middle East fine printing of illustrated books is a very recent development. The lavish King Fuad Qur'an (1923, Egypt) is exceptional among Middle Eastern printed works. In East Asia the art of book illustration is very old. Printing was highly developed in China by the 9th cent., and exquisite block-printed illustrations enhanced many volumes. Japan borrowed Chinese techniques as early as the 9th cent. and used the ancient processes for wood-block printing of ukiyo-e (see Japanese art) in books into the 18th cent. Twentieth-century printing of illustrated books in Japan involves the best and most recently developed processes.