Nonlinear Structures & Systems, Volume 1: Proceedings of the 42nd IMAC, A Conference and Exposition on Structural Dynamics, 2024, the first volume of ten 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 Nonlinear Dynamics, including papers on:Experimental Nonlinear DynamicsJointed Structures: Identification, Mechanics, DynamicsNonlinear DampingNonlinear Modeling and SimulationNonlinear Reduced-Order ModelingNonlinearity and System Identification