Abstract: The joint U.S. and German Stratospheric Observatory for Infrared Astronomy (SOFIA) will be a premier observatory facility during future decades for studying the physics and chemistry of stellar evolution processes. Utilizing the large suite of science instruments and the broad wavelength coverage of SOFIA, astronomers will be armed with unique capabilities to undertake a large breadth of investigations ranging from studies of the Solar System to the star forming history of galaxies over cosmic time. SOFIA is a German-built 2.5-meter telescope mounted in a modified Boeing 747-SP aircraft supplied by NASA. Flying at altitudes as high as 45,000-feet, SOFIA will be above most of atmospheric water vapor that severely limits the ability to do infrared and sub-mm observations using ground-based telescopes. SOFIA's first-generation instruments include broadband imagers, moderate resolution spectrographs capable of resolving broad features due to dust and large molecules, and high resolution spectrometers suitable for kinematic studies of molecular and atomic gas lines at suitable resolution. SOFIA science applications will be discussed, with special emphasis on investigations related to infrared spectroscopy of astrophysical gas, grains and ices. Although the primary impact of SOFIA will be its scientific return, SOFIA's other major advantages include the provision of a platform on which to demonstrate new future technologies and to provide in-flight experience to young scientists, educators and journalists.