An ever increasing variety of material is available today, with each having its own advantages, attributes application and limitations. Material selection is one of the major points that should be taken into account seriously in the engineering design stage. The selection of an optimal material for an engineering design from among two or more alternative materials on the basis of two or more attributes is a multiple attribute judgment. Therefore, the design engineer should be directed with an expert system for selecting the most suitable material as well as predicting the properties of a unknown material. This book aims at development of an expert system for material selection using artificial neural network and to predict the properties of unknown material to help the design engineer in his decision making process. The expert system presents a logical procedure for material selection for a given engineering design.