The research in theoretical gravitational physics will include: The role of short distance physics in black hole radiation via the Hawking process and in particle production in an expanding universe; Observational limits on, and theoretical properties of, higher derivative effective actions for the gravitational field; Black hole thermodynamics for such effective actions; The effort to identify a statistical origin for black hole entropy; Cutoff models for spacetime structure via the algebra of quantum field operators and causal networks; Results of this research should lead to a better understanding of the sensitivity of particle production in gravitational fields to unknown short distance physics, possible corrections to the Einstein equations, and of the nature and range of validity of the laws of black hole thermodynamics. The research may also lead to predictions following from the existence of a fundamental short-distance cutoff on physical degrees of freedom, and/or yield insights valuable in attempts to supplant the continuum model of spacetime by a finitistic one.