The Earth's Climate and its Response to Solar Variability: The Climate System -- Atmospheric Dynamics, Modes of Variability and Climate Modelling -- Climate Records -- Radiative Processes in the Atmosphere -- The Greenhouse Effect and Radiative Forcing of Climate Change -- Clouds -- Atmospheric Photochemistry -- Response of Climate to Variations in Solar Irradiance -- The Earth's Electric Field and Ionisation of the Atmosphere -- Conclusions -- Solar Outputs, Their Variations and Their Effects on Earth: Introduction to the Sun and the Solar Activity Cycle -- Fundamental Plasma Physics of the Sun and Heliosphere -- The Heliosphere, Cosmic Rays and Cosmogenic Isotopes -- Solar Irradiance Variations -- Variability on Century Timescales -- Implications for Earth's Climate -- Conclusions and Implications -- Stellar Analogs of Solar Activity: The Sun in A Stellar Context: Introduction -- Stellar Cycles -- Brightness Changes in Solar-Type Stars -- Activity in Solar Analogs -- Stellar Surface Inhomogeneities -- The Coronae of Solar Analogs, Low Mass Stars, and Brown Dwarfs -- The Early Sun -- Stellar Activity and Extrasolar Planets -- Index.