The Near Saturn Magnetic Field Environment This thesis focuses on the very high Mach number shock wave that is located sunward of Saturns strong magnetic field in the continuous high speed flow of charged particles from the Sun (the solar wind). The author exploits the fact that the Cassini spacecraft is the only orbiter in a unique parameter regime far different from the more familiar near Earth space to provide in situ insights into the unreachable exotic regime of supernova remnants. This thesis bridges the gap between shock physics in the Solar System and the physics of ultra high Mach number shocks around the remnants of supernova explosions since to date research into the latter has been restricted to theory remote observations and simulations. Introduction to Space Plasmas The Sun Saturn Connection Spacecraft and Instrumentation Magnetic Field Characterisation of Saturn’s Bow Shock Quasi perpendicular High Mach Number Collisionless Shocks The Magnetic Structure of Saturn’s Magnetosheath Summary and Perspective Bibliography.