Jupiter is a planet of superlatives: the most massive planet in the solar system, rotates the fastest, has the strongest magnetic field, and has the most massive satellite system of any planet. These unique properties lead to volcanoes on Io and the existence of energetic plasma in the Jovian system that provides a physical link between the satellites, particularly Io, and Jupiter. Although it has been know for over 30 years that Io modulates Jupiter's radio emissions, only very recently has the direct connection been demonstrated.  This talk presents recent explorations of Jupiter's vast and dynamic magnetosphere  by Galileo, Hubble Space Telescope and Cassini.