Hand composing was rendered commercially obsolete by continuous casting or "hot-metal" typesetting machines, such as the Linotype machine and Monotype at the end of the 19th century. The Linotype, invented by Ottmar Mergenthaler, enabled one machine operator to do the work of ten hand compositors by automating the selection, use and replacement of sorts, with a keyboard as input. Later advances, such as the typewriter or computer, pushed the state of the art even farther ahead. Still, hand composition and letterpress printing did not fall completely out of use. Since the introduction of digital typesetting, it has seen a renewal as an artisanal pursuit. However, it is a very small niche within the larger typesetting market.