As we enter an exciting new era in industrial design, simulation, and manufacturing, a clear understanding of mechanics of solids is needed now more than ever. This primer  is a condensed synopsis of basic undergraduate mechanics and is designed to supplement  classical textbooks in this area. The focus is  on the essentials of mechanics, specifically: •             The concept of stress. •             Stress-strain relationships. •             Failure theory. •             Axial loading of a rod. •             Transverse (bending) loading of a beam. •             Industrial application: modeling of 3D printing. •             Transverse shear stresses. •             Torsional loading of a rod. •             Pressure vessels. •             Buckling of columns. •             The basics of finite element methods. •             A unifying concept: continuum mechanics.