An Engineering Companion to Mechanics of Materials is the first volume in the Momentum Press collection The Modern Engineering Companions: A Systems Approach to the Study of Engineering. In Mechanics of Materials, we apply the intuitive "systems approach" to learning, the advantages of which are several. The student first gets a broad overview of the entire subject rather than the narrow piecemeal vision afforded by the traditional "component approach" common to most engineering texts. Mechanics of Materials comes with additional features to improve student learning, including Common Confusing Concepts (C3) noted and clarii ed, indication of key concepts, side bar discussions, worked examples, and exercises for developing engineering intuition. The Companions are intended as a supplementary resource to help both undergraduate, graduate, and post-graduate students better learn and understand engineering concepts.