Prior to the arrival of Cassini at Saturn in July 2004, the spacecraft sampled the solar wind and interplanetary magnetic field (IMF) upstream of the planet. It found a highly structured interplanetary medium dominated by compressions and rarefactions associated with corotating interaction regions (CIRs). We discuss the impact of this on the solar wind interaction with Saturn.s magnetosphere, with special focus on the role of dayside reconnection. Since its arrival at Saturn, Cassini has explored many regions of Saturn.s intriguing magnetosphere, and we focus particularly on the nightside region. We discuss the first in situ observations of magnetotail reconnection at Saturn, and compare and contrast them with the same process at other planets. We address the issue of the roles of solar wind interaction versus rapid planetary rotation in driving magnetotail dynamics. Features observed in the magnetotail with magnetometer, plasma and energetic particle instruments are presented and are linked to the current hot topic of magnetospheric periodicities at Saturn. We also discuss the auroral and radio emissions from Saturn, highlighting how these can be used as diagnostic tools to remotely sense magnetospheric dynamics.