My primary research interests are in the measurement and interpretation of anisotropies of the cosmic microwave background (CMB). Primary anisotropies of the CMB provide a probe of the universe at the time when the CMB photons last interacted with the matter. Measurements of CMB anisotropies place strong constraints on cosmological models. Within the context of a given model, high sensitivity measurements of the power spectrum of the CMB can be used to precisely determine cosmological parameters such as the density of energy and baryonic matter in the Universe. Hot electrons bound to clusters of galaxies Compton scatter the photons of the CMB. The resulting distortion of the incident blackbody spectrum in the direction of a cluster of galaxies – the Sunyaev-Zel'dovich (SZ) Effect - can be used as a sensitive probe of cosmology and cluster physics. Combining measurements of the SZ effect with X-ray observations provides a unique and physically based determination of the distance scale of the Universe and cluster baryon fraction. In addition, source counts of distant SZ clusters probe the growth of structure and provide constraints on the equation of state of the dark energy which is believed to dominate the dynamics of the Universe. Due to advances in the detector technology and observation strategy, the sensitivity of CMB anisotropy experiments is rapidly increasing. My group is actively involved in the design, construction and operation of several new CMB anisotropy projects as well as the development of cryogenics, electronics, optics, and detectors to enable future advances in this rapidly maturing field.