Topics in Nonlinear Dynamics, Volume 1: Proceedings of the 31st IMAC, A Conference and Exposition on Structural Dynamics, 2013, the first volume of seven from the Conference, brings together contributions to this important area of research and engineering. The collection presents early findings and case studies on fundamental and applied aspects of Structural Dynamics, including papers on: Nonlinear OscillationsNonlinearities In PracticeNonlinear System Identification: MethodsNonlinear System Identification: Friction & ContactNonlinear Modal AnalysisNonlinear Modeling & SimulationNonlinear Vibration AbsorbersConstructive Utilization of Nonlinearity