In what did the improvement consist? First let us call to mind what the book-maker in the early part of the 15th century had to begin with; he had paper, he had printing-ink, he had skill in engraving whole pages for block-books, and he had a rude kind of printing-press. The improvement consisted in this: Instead of engraving a whole page on a block, single letters were engraved on little blocks called types, and when a word or a line or a page was to be printed these types were set in the position desired; in other words, the improvement consisted in the invention of _moveable types_. The types were first made of wood and afterward of metal. [Illustration: FIG. 11.--AN EARLY PRINTING PRESS.] The great advantage of the moveable types over the block-book is easily seen. A block containing, say, the word "post" is useless except for printing the word _post_; but divide it into four blocks, each containing a letter: now you can print _post_, _spot_, _tops_, _stop_, _top_, _sop_, _sot_, _pot_, _so_, _to_ and so forth. The exact date of the invention of moveable types cannot be determined. We can only say that they were first used between 1450 and 1460. Nor can we tell who invented them. The Dutch claim that Lawrence Koster of Harlem (Holland) made some moveable types as early as 1430, and that John Faust, an employee, stole them and carried them to Mayence (Germany), where John Gutenberg learned the secret of printing with them. The Germans claim that Gutenberg was the real inventor. Much can be said in behalf of both claims. What we really know is that the earliest complete book printed on moveable types was a Bible which came from the press of John Gutenberg in 1455. Since 1450 there has been no discovery that has changed the character of the printed volume. There have been wonderful improvements in the processes of making and setting type, and printing-presses (Fig. 11) have become marvels of mechanical skill, but the book of to-day is essentially like the book of four hundred years ago. The tablet of the memory, the knotted cord and notched stick, the uncanny picture-writing, the clumsy picture-sign, the alphabet, the manuscript volume, the printed block-book and the volume before you bring to an end the story of the book. FOOTNOTE: [20] The illustration is taken from Keary's "Dawn of History." THE MESSAGE Men had not been living together long in a state of society before they found it necessary to communicate with their fellow-men at a distance and in order to do this the _message_ was invented. We have seen (p. 205) that among certain tribes of savages notched sticks bearing messages were sent from one tribe to another. Among the ancient Peruvians the message took the form of the curious looking quipu. After the alphabet had been invented and papyrus had come into use as a writing material, the message took the form of a written document and resembled somewhat the modern _letter_.