In 1978, the European Mechanics Committee and the French Centre National de la Recherche Scientifique agreed to the organization of an Interna tional Colloquium on the "Mechanical Behavior of Anisotropic Solids". The meeting was held at Villard-de-Lans (near Grenoble, France) from 19th to 22 nd June 1979. The Colloquium considered mechanical aspects of the anisotropy of solids, both initial and induced by permanent deformation, anisotropic hardening and damage, oriented fissuration, etc. Topics concerned mathematical, experimental and engineering aspects of the anisotropy of metals, composites, soils and rocks. The aim of the Colloquium was to bring together experimentalists, theoretecians and engineers interested in various features of mechanical anisotropy, in order to permit an interdisciplinary exchange of understanding, experience and methods. A detailed description of the scope, aim and proposed topics is contained in the Preface. The announcement of the Colloquium attracted a large number of sub mitted contributions. Conforming with the principles of Euromech Colloquia and of the Colloques Internationaux du CNRS, the accepted contributions were limited to 50 communications. A general description of the scientific program is to be found in the Preface. Five general lectures gave state-of-the-art reports concerning some areas of the behavior of anisotropic solids; the 50 communications were divided into 12 sessions dealing with specific topics (see "Contents"). In order to facilitate subsequent contact between the reader and the contributors, full addresses are given in the "List of Authors."