This research program focuses on the experimental study of the dynamic evolution of prepared quantum states, the transition between the semiclassical and quantal regimes, and the response of a quantum system to non-classical excitation. The experiments will be conducted in a cavity QED apparatus, where optically pumped atoms interact with a single mode of a driven high finesse optical cavity. The investigations will probe dissipative quantum processes and will help elucidate questions of continuous quantum measurement for open systems.