Recent Developments in Particle Symmetries focuses on the advancements of processes, technologies, reactions, transformations, and approaches in particle symmetries. The selection first offers information on higher symmetries and deviations from unitary symmetry, including S matrix and perturbation theory and bootstrap theory of octet enhancement. The text then ponders on broken symmetries and sum rules and difficulties of relativistic U(6). Discussions focus on covariant models, unitary, Coleman's theorems, saturation of commutation relations and particle multiplets, and exact internal symmetry. The manuscript elaborates on CP violation, K decay and CP violation, and proton-antiproton annihilations at rest. The text then takes a look at the value of internal symmetries, low-energy hyperon-proton interactions, and strange resonances. Discussions focus on mesonic and baryonic resonances, hierarchy of internal symmetries, well-ordered violation of internal symmetries, and the combination of internal and geometrical symmetries in the physics of elementary particles. The selection is a valuable source of information for readers wanting to study particle symmetries.