As has been pointed out by many of the writers on the subject, the so-called invention of printing was not so much the result of an individual inspiration, as the almost inevitable consequence of a long series of experiments and of partial processes which had been conducted in various places where the community was interesting itself in the multiplication of literature. If, as is probably the case, the first book printed from movable type is to be credited to Koster, it remains none the less the case that Gutenberg’s process must have been worked out for itself, and that the German possessed, what the Hollander appears to have lacked, not merely the persistence and the practical understanding required to produce a single book, but the power to overcome obstacles and to instruct others, and was thus able to establish the new art on a lasting foundation. The claims of the Hollanders under which Koster is to be regarded as the first printer, or at least (bearing in mind the Chinese precedents in the tenth century) the first European printer, from movable type, claims which Humphreys accepts as well founded, are in substance as follows: Laurence Koster was born, somewhere in Holland, about 1370, and died in Haarlem about 1440. He is believed to have made his first experiments with movable wooden types about 1426, and to have worked with metal types about ten years later. The principal of the earlier authorities concerning Koster’s career is a certain Hadrian Junius, who completed, in 1569, a history of Holland, which was published in 1588. He speaks of Koster as being a man of an honourable family, in which the office of Sacristan (custos, Coster or Koster) was hereditary, and he describes in detail the development of the invention of type, from the cutting of pieces of beech-bark into the form of letters, to the final production of the metal fonts. Junius goes on to relate the method under which Koster’s first book (from type), _Speculum Humanæ Salvationis_, was printed, in 1430. This book, the origin of which is not known, had for many years been popular among the Benedictines, and few of their monasteries were without a copy. As a result of this popularity, many examples of the manuscript copies have been preserved, some of which are in the Arundel collection in the British Museum. Zani says that the _Speculum_ was compiled for the assistance of poor preachers, and in support of this view he quotes certain lines, which may serve also as an example of Latinity and of the general style: _Predictum prohemium hujus libri de contentis compilavi Et propter pauperes predicatores hoc opponere curavi._[424]