A support with a slanted top, for holding an open book at a slight angle, so as to improve textual accessibility; also known as "bookrest", "lectern", "book easel", "podium", "bookrack", or "bookstall". In Medieval libraries, where volumes were commonly chained to their stowage shelf or chest, and where artificial illumination was a hazard to both the collection and the readers, bringing the book nearer to some natural light was crucial; so pivoting podiums, rotating lecterns, and revolving book wheels were devised as essential furniture. See book press, carrel, scriptorium, kiosk.