The first manuscripts were kept in boxes by a few very rich collectors or in monestries. With the developement of printing books became available to a greater number and in the early 18th C the first bookcases appear. They were often made in exotic woods such as mahogany, rosewood or satinwood with marquetry inlay. Bookcases are often in two parts with full lower doors and glazed upper doors. Lower bookcases often have marble tops. The shelves are usually adjustable for fitting different sized books or even objects. The late 19th C saw the arrival of the revolving bookcase, very popular in the early 20th C.