It is very likely that the European idea of cutting block books was borrowed from China, and here from the later half of the fifteenth century until the earlier half of the sixteenth century such books were produced plentifully in Germany, Holland, and England, and more rarely in France. Single-sheet pictures were made at first, the earliest dated example known being the “St. Christopher” of 1423, now in the Rylands Library in Manchester. From being cut on wood these curious prints are generally known as xylographs. Criticism and comparison of them is a very difficult matter, as they were designed and cut on such broad and easy lines that they were easily copied almost exactly, but now all the important and very early specimens are so well known and have been so carefully listed and described by competent bibliographers like Mr. Gordon Duff, Sir Martin Conway, Hain, Ottley, Bradshaw, Hessels, Proctor, and others, that there is little risk of fraudulent imitation remaining long unrecognised. The block book proper however, shows text as well as illustrations, the text gradually becoming more and more important. Block books are printed in pale coloured ink, so that they may take colour as well as possible, and are usually coloured more or less, sometimes by hand and sometimes by means of stencil plates, or perhaps a combination of both methods. Many of them are astronomical, but as a rule the subjects are more or less religious, such as the “Ars Moriendi” or “Biblia Pauperum”; the illustrations and the text being variously arranged. Each page is cut on one block, sometimes printed page by page, sometimes two pages at a time, and always on one side of the paper only. Now and then, as in the case of the “Speculum Humanae Salvationis,” the text is separately cut; this remarkable book is supposed to have been printed at Utrecht about 1470-72. Block books are always printed on paper of excellent quality. Printing from moveable types in Europe is considered by many authorities to have been invented by Laurens Janszoon Coster, of Haarlem, during the earlier half of the fifteenth century. Actual proofs are wanting, but there exist several books and fragments of books, many of which have been recovered from the boards of old bindings, which certainly are not the work of Gutenberg. These fragments were printed in Holland, and are known as “Costeriana”; several of the letters used correspond to the Dutch manuscript letters of the time, and many of them are copies of the school books known as “Donatus’.” Some of the letters look much as if they had been cut in wood. At Avignon it is recorded that in 1444 experiments with printing types were made. The Coster legend appears to have been started by Adrianus Junius, who in his _Batavia_, published at Antwerp in 1588, speaking of Haarlem, says: “Redeo ad urbem nostram cui primam inventae ist hic artis typographical gloriam deberi.”