Research will center on two problems: (1) laser spectroscopy of the diamagnetic Rydberg atom; (2) measurement of the Rydberg constant. The diamagnetic Rydberg atom is the prototype for simple atomic systems described by a non-separable Hamiltonian, a challenge for quantum theory. The system is relevant in studying the relation between quantum structure and nonlinear dynamics, since its classical motion undergoes a transition to chaos. Well ordered quantum levels have now been found in regimes believed to be irregular and these investigations will be continued. In the second problem the Rydberg constant will be measured by measuring millimeter wave transitions between Rydberg states of hydrogen. This will lead to an improved valve for a key fundamental constant.