Description:''The objective of the Third Congress is to ascertain on an international scale the advances in roch mechanics during the years since the Second ISRM Congress and to indicate directions for further effort. Five major sub-fields of rock mechanics were chosen as themes for the Congress: Theme I, Physical Properties of Intact Rock and Rock Masses; Theme II, Tectonophysics; Theme III, Surface Workings; Theme IV, Underground Openings; and Theme V, Fragmentation Systems