Abstract: An improved X-Y-.theta. positioning mechanism or stage having a rectangular platform (2) upon which a workpiece to be moved is placed. The platform is positioned by bearings (6a, 6b), which ride along its edges. In the preferred embodiment, the bearings are mounted to the ends of perpendicularly overlapping tracks (8x, 8y). The tracks are linearly movable via corresponding forcing elements or motor coils (10x, 10y). The forcing elements are fixedly mounted to a main structure (14), to dissipate heat efficiently. Also in the preferred embodiment, positioning feedback for the stage includes an X-Y scale (4). Position sensors (12a, 12b) are mounted fixedly to the main structure directly under the X-Y scale. .theta. rotation is achieved when two tracks are used for the same X or Y axis, so that the platform rotates as these two tracks are positioned slightly offset from one another.