Coster, Or Roster, Laurens Janszoon, a Dutch mechanic, considered by his countrymen the inventor of the art of printing, born in Haarlem about 1370, died about, 1440. The account given of him is, that having made his invention in Haarlem previous to Gutenberg, he obliged the workmen in his employ under oath not to divulge his secret, but that after his death one of them, Johann Faust, or more probably Jo-hann Gutenberg, took possession on a Christmas night of all his master's implements and types, and fled to Amsterdam, thence to Cologne, and afterward to Mentz, where he founded a printing establishment. The documents by which the supporters of Coster attempt to establish his claims are of comparatively recent discovery, but his countrymen have made this question one of national importance. A statue, with an inscription commemorative of the invention of printing, was raised at Haarlem in 1622 in his honor, opposite the house which he occupied. The academy of Haarlem having offered a prize for the best vindication of Coster's claim, it was awarded to Koning's Ver-handeling over het oorsprojig, etc, der ooeJc-druklcunst (Haarlem, 1816; translated into French, 1819). A committee appointed by the authorities of Haarlem agreed upon 1423 as the year in which the art of printing had been invented by their townsman, and the fourth jubilee in honor of that event, called the " Coster festival," was celebrated with great pomp on July 11 and 12, 1823, when a monument to him was erected in the Haarlem wood.

On July 16, 1856, a statue of him was erected in the market place of that city. - See Gedenk-schriften wegens het vierde eeuw-getijde van de uitvinding der boekdrukkunst (Haarlem, 1824).