Professor Hartmann will continue his studies of quantum optics, the interaction of radiation fields with atoms. Cooperative cascade superfluorescence will be studied in a three- level system. Superfluorescence is a collective effect occurring when an ensemble of atoms are stimulated to emit radiation in phase. Cascade superfluorescence takes place when a collection of atoms, initially prepared in an excited state, emit to an intermediate state, and finally cascade to a lower-lying final state. The time evolution of the radiation, its intensity and direction of emission, will provide new insight into the way quantized radiation fields interact with quantized atomic systems.