Sub-mm tests of the gravitational inverse-square law

Sub-mm tests of the gravitational inverse-square law are interesting from several quite different perspectives. This paper discusses work by the Eot-Wash group performed since the publication of our initial result in February 2001. We find no evidence for short-range Yukawa interactions. Our results provide an upper limit of 200 micrometers on the size of the largest ``extra'' dimension, and for the unification scenario with 2 large extra dimensions, set an upper limit of 150 micrometers on the size of those dimensions