Following in the mould established by precursors at Fermilab and SLAC, the 4th International Symposium on the History of Particle Physics will bring together leading physicists who have worked in the field with historians, philosophers and other scholars of science who study the discipline. The focus of this symposium will be upon the important discoveries and intellectual currents of the 1980s and 1990s — a period in which Europe and especially CERN became the acknowledged center of gravity in particle physics. Theoretical, experimental and accelerator physics developments will be examined, as well as the marriage of particle physics with cosmology and astrophysics. This symposium will occur at CERN on 10-13 November 2025.