"The past fifteen years of laboratory-scale gravitational experimentation have been marked by many new and exciting developments. The field received a lot of impetus by the hypothesis of a ”” ... in 1986. This very testable new force would have been a blatant violation of the equivalence principle. The evidence for the 5th force was partially based on a reanalysis of the torsion balance data of of the early 1900’s. Immediately several groups around the world started to do . The availability of new technologies combined with many new and creative ideas quickly led to several refined measurements by which the 5th force in its postulated form could be conclusively ruled out. However, the physics community was once again reminded of the importance of the equivalence principle which lies at the foundation of general relativity. Tests of the equivalence principle become particularly important for , most of which predict an equivalence principle breakdown at some level. In addition it is generally believed that the can only be complete with the existence of new particles which could exist at high masses as well as at the ultra low energies. The latter frontier being covered by laboratory-gravity tests."