GNSS Occultation: Methodology, Analysis, and Applications -- GPS Radio Occultation with CHAMP, GRACE-A, SAC-C, TerraSAR-X, and FORMOSAT-3/COSMIC: Brief Review of Results from GFZ -- Error Estimate of Bending Angles in the Presence of Strong Horizontal Gradients -- Phase Transform Algorithm for Radio Occultation Data Processing -- Using Airborne GNSS Receivers to Detect Atmospheric Turbulence -- The GRAS SAF Radio Occultation Processing Intercomparison Project ROPIC -- Radio Occultation Soundings in Ionosphere and Space Weather Applications: Achievements and Prospects -- Solar, Lunar, and Stellar Occultation for Atmospheric Studies -- SCIAMACHY Solar Occultation: Ozone and NO2 Profiles 2002-2007 -- Retrieval of Trace Gas Concentrations from Lunar Occultation Measurements with SCIAMACHY on ENVISAT -- Validation of GOMOS/Envisat High-Resolution Temperature Profiles (HRTP) Using Spectral Analysis -- GNSS Occultation for Atmospheric Studies -- Assimilation of Radio Occultation Data in the Global Meteorological Model GME of the German Weather Service -- Sampling of the Diurnal Tide of Temperature Using Formosat-3/COSMIC Data -- Recent Advances in the Study of Stratospheric Wave Activity Using COSMIC and CHAMP GPS-RO -- Recent Advances in Gravity Wave Analysis from Long Term Global GPS Radio Occultation Observations -- New Applications and Advances of the GPS Radio Occultation Technology as Recovered by Analysis of the FORMOSAT-3/COSMIC and CHAMP Data-Base -- GNSS Occultation for Climate Studies -- Climatologies Based on Radio Occultation Data from CHAMP and Formosat-3/COSMIC -- Testing Climate Models Using Infrared Spectra and GNSS Radio Occultation -- Construction of Consistent Temperature Records in the Lower Stratosphere Using Global Positioning System Radio Occultation Data and Microwave Sounding Measurements -- Lower Stratospheric Temperatures from CHAMP RO Compared to MSU/AMSU Records: An Analysis of Error Sources -- SimVis: An Interactive Visual Field Exploration Tool Applied to Climate Research -- Trend Indicators of Atmospheric Climate Change Based on Global Climate Model Scenarios -- Future Occultation Missions -- ROSA - The Italian Radio Occultation Mission Onboard the Indian OCEANSAT-2 Satellite -- Radio Occultation Mission in Korea Multi-Purpose Satellite KOMPSAT-5 -- The Contribution of PROBA2-LYRA Occultations to Earth Atmosphere Composition Analysis -- The Active Temperature, Ozone and Moisture Microwave Spectrometer (ATOMMS). This book presents carefully edited and peer-reviewed papers from the 3rd International Workshop on Occultations for Probing Atmosphere and Climate (OPAC-3), held in Graz, Austria. Starting with an overview on occultation methodology and its applications, the topics comprise the use of occultation data in numerical weather prediction and atmospheric wave analysis as well as in climate monitoring and change research. It covers results from current radio occultation missions (CHAMP to Formosat-3/COSMIC) and from solar, lunar, and stellar occultation by the SCIAMACHY and GOMOS instruments onboard ENVISAT. Presenting as well upcoming occultation missions and new concepts, this work provides comprehensive insight and is a key reference on the current status in the field and towards new horizons in occultation research.