This book comprises the select peer-reviewed proceedings of the 14th International Symposium on Plasticity and Impact Mechanics (IMPLAST) 2025, which was held at the Indian Institute of Technology Roorkee, Roorkee, India. The article collections in this volume are primarily focused on theoretical and computational developments in plasticity and damage mechanics. It plunges into advanced constitutive models that capture material nonlinearity, large deformation, irreversible deformation, hardening/softening, and progressive failure. The book includes classical and modern plasticity theories, coupled plasticity-damage formulations, and continuum damage mechanics. It also explores thermodynamically consistent modelling, micromechanics-based laws, advanced AI/ML approaches for crack detection and topology optimisation, and the prediction of localisation phenomena. Applications span metals, concrete, polymers, and composites under monotonic, cyclic, and dynamic loading. Featuring benchmark simulations, numerical solution strategies, and validations, this volume is a key reference for researchers developing material models and for engineers analysing structural performance beyond the elastic limit.