This book provides a fundamental understanding of the analytic process involved in solving complex problems, such as the influence of geometric nonlinearity on buckling, vibration, and second-order displacements. Because the book assumes linear behavior the solution can be evaluated using matrix math. Computer software, however, must be used to account for possible nonlinear material behavior due to the local yielding of the members that would result in changes to the elements of the stiffness matrix. Hence the computer solution must be iterative. The number of iterations and the iteration interval may be set manually by the user or internally by the software which can affect the solution.