2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/230917The powerful wind-wind collision in massive star binaries creates a region of high temperature plasma and accelerates particles to relativistic energies. I briefly summarize the hydrodynamics of the wind-wind interaction and the observational evidence, including recent $γ$-ray detections, of non-thermal emission from such systems. I then discuss existing models of the non-thermal emission and their application to date, before concluding with some future prospects.Invited review at HEPIMS Workshop (Jaen 2009); 12 pages, 5 figures, to appear in PASPHigh Energy Astrophysical PhenomenaSolar and Stellar Astrophysicstext