This lecture explores the multi-messenger probes of cosmological magnetic fields, including gamma-ray, UHECR, Faraday rotation, CMB, and SGWB measurements. It delves into the generation of magnetic fields in astronomical objects, the QCD phase transition, and the evolution of cosmological magnetic fields through turbulence. The discussion covers the detection of relic volume-filling fields, the impact of magnetic fields on CMB, and the potential of pulsar timing arrays and gravitational wave detectors in studying cosmological magnetic fields.