The Sun is an extremely dynamic star and strong changes take place on it on different time scales. Whatever changes take place on the sun, whether long term or short term, does not remain confined to the solar atmosphere only but also produce large scale disturbances in the interplanetary medium as well as planetary environments. The sun emits large fluxes of short wave length radiations. These radiations impinge on the top of atmosphere of earth and ionize the gasses present there and the density of ions and electrons are increased which significantly affects the propagation of electromagnetic waves and signals passing through it. Due to this satellite communication, navigational and surveillance applications are badly affected. In this book we have presented the response of geospace to solar eruptive processes on the magnetosphere and ionosphere of the earth.