This document provides an excerpt from the textbook "Mechanics of Materials" by Ferdinand P. Beer, E. Russell Johnston, Jr., and John T. DeWolf. The excerpt discusses columns and their stability. It begins by explaining how column design considers both stress and deformation. It then introduces Euler's formula for calculating the critical buckling load of columns. Subsequent sections extend the formula to other column end conditions, provide sample problems, and discuss design of columns under centric and eccentric loading. Key concepts covered include pin-ended beams, the secant formula for eccentric loading, and design approaches for steel and aluminum alloy columns.