Abstract: An adjustable auxiliary work surface assembly which includes a shelflike auxiliary work surface which is suitably connected to one end of a linkage, specifically a parallelogram linkage. The other end of this linkage is in turn connected to a carriage which is suitably rollingly supported within horizontally elongated guide rails, the latter being fixedly secured to the underside of a primary work surface. The parallelogram linkage enables the auxiliary work surface to be vertically swung upwardly and downwardly. This parallelogram linkage has a manually actuated lock so that the operator can lock the linkage at any selected elevation of the auxiliary work surface. In addition, the carriage can be rollingly moved so as to position the auxiliary work surface in a desired use position adjacent the edge of the primary work surface.