“Multi Messenger Astronomy” explores a revolutionary approach to understanding the universe by combining data from electromagnetic radiation, gravitational waves, neutrinos, and cosmic rays. This interdisciplinary field overcomes limitations of traditional astronomy, which is often hindered by interstellar dust. By studying multiple “messengers,” scientists gain a more complete picture of astrophysical events like black hole mergers and neutron star collisions. For instance, gravitational waves, ripples in spacetime, and neutrinos, nearly massless particles, offer unobstructed views of cosmic phenomena. The book guides readers through the properties of each messenger and explores astrophysical sources emitting multiple signals, such as gamma-ray bursts. It highlights how combining data has already led to significant discoveries and promises to address outstanding questions in Science Physics and astrophysics. The approach emphasizes collaborative research and interdisciplinary connections, showcasing the power of integrating particle physics and advanced computing. The book progresses from introducing fundamental properties of each messenger to exploring specific astrophysical sources, culminating in future prospects of new observatories and experimental techniques.