The Solar Radiation and Climate Experiment (SORCE) Mission for the NASA Earth Observing System (EOS) -- The SORCE Mission -- SORCE Contributions to New Understanding of Global Change and Solar Variability -- An Overview of the Disposition of Solar Radiation in the Lower Atmosphere: Connections to the SORCE Mission and Climate Change -- The SORCE Spacecraft and Operations -- The Total Irradiance Monitor (TIM): Instrument Design -- The Total Irradiance Monitor (TIM): Instrument Calibration -- The Total Irradiance Monitor (TIM): Science Results -- The Spectral Irradiance Monitor: Scientific Requirements, Instrument Design, and Operation Modes -- The Spectral Irradiance Monitor: Measurement Equations and Calibration -- The Spectral Irradiance Monitor (SIM): Early Observations -- Solar-Stellar Irradiance Comparison Experiment II (SOLSTICE II): Instrument Concept and Design -- Solar-Stellar Irradiance Comparison Experiment II (SOLSTICE II): Pre-Launch and On-Orbit Calibrations -- Solar-Stellar Irradiance Comparison Experiment II (SOLSTICE II): Examination of the Solar-Stellar Comparison Technique -- The Mg II Index from SORCE -- XUV Photometer System (XPS): Overview and Calibrations -- XUV Photometer System (XPS): Solar Variations During the SORCE Mission -- The SORCE Science Data System.This book describes the state-of-the art instruments for measuring the solar irradiance from soft x-ray to the near infrared and the total solar irradiance. Furthermore, the SORCE mission and early results on solar variability are presented along with papers that provide an overview of solar influences on Earth.