Musaeum Clausum, also known as Bibliotheca abscondita, is a tract written by Sir Thomas Browne which was first published posthumously in 1684. The tract contains short sentence descriptions of supposed, rumoured or lost books, pictures, and objects. The subtitle describes the tract as an inventory of remarkable books, antiquities, pictures and rarities of several kinds, scarce or never seen by any man now living. Its date is unknown: however, an event from the year 1673 is cited.