Using a fresh, modern approach to the mechanics of materials, this book focuses on a unified mechanistic approach that uses energy concepts for modeling a large range of engineering material behavior. In the presentation, 1D-Think models lead to the development of various fundamentals of continuum mechanics, such as deformation and strain, momentum balance, stress and stress states, thermoelasticity and elasticity bounds, plasticity and yield design. The bases for a common language among core disciplines in engineering sciences are developed in a mathematical manner.