Significant forces between dielectric objects can be induced by intense optical fields. We discuss the origin of these forces which are very long range and oscillate in sign at the optical wavelength. A consequence is that light waves can serve to bind matter in new organized forms. We experimentally demonstrate the simplest case by observing a series of bound states between two 1.43-μm-diam plastic spheres in water, and discuss the extension to more complex cases. ; Physics ; Version of Record