The infrared and bolometric luminosities of elliptical galaxies and the bulges of spiral galaxies are dominated by light from K and M giants. The objective of this project is to determine the physical characteristics of such stars of different ages and compositions and in different environments. This will be accomplished using infrared spectroscopy and photometry supplemented by some optical spectroscopy. The implications include testing and calibrating models of stellar interiors and evolution and information on the stellar systems themselves. The results will also be useful for future investigations of the integrated light from stellar systems.