Topics in Modal Analysis, Testing & Parameter Identification, Volume 9:  Proceedings of the 42nd IMAC, A Conference and Exposition on Structural Dynamics, 2024, the nineth 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 Modal Analysis, Modal Testing and Modal Parameter Identification including papers on:Analytical MethodsModal ApplicationsBasics of Modal AnalysisExperimental TechniquesMulti Degree of Freedom TestingBoundary Conditions in Environmental TestingOperational Modal AnalysisModal Parameter IdentificationNovel Techniques