This text is concerned with the mechanics of rigid and deformable solids in equilibrium. It has been prepared by members of the Mechanical Engineering Department at the Massachusetts Institute of Technology for use as a text in the first course in applied mechanics. The central aim has been to treat this subject as an engineering science. To this end the authors have clearly identified three fundamental physical considerations which govern the mechanics of solids in equilibrium, and all discussion and theoretical development has been related to these basic considerations.