The principal focus of my group is on the theoretical aspects of cosmological probes of dark energy, dark matter, and inflation: (i) constructing new statistical techniques to extract the greatest amount of information from cosmological datasets; (ii) questioning the underlying astrophysical assumptions of observational programs, identifying previously unappreciated systematic errors, and developing techniques to correct them; and (iii) identifying new features of the standard cosmological model (with dark matter and dark energy in addition to normal matter) and alternatives, and using them to build new cosmological tests. I work closely with observers and try to address their needs, both in terms of predicting phenomena as well as in developing optimal data analysis methods.