Our group designs and micro-fabricates custom devices that achieve sensitivity at fundamental limits and are based on the principles of superconductivity. We often work in large collaborations to apply these devices to challenging measurements of high scientific interest, such as those which characterize the detailed physical evolution of the universe at large. For more details on our astronomical applications, see Measuring the Cosmos. Terrestrial applications focus on several aspects of microwave metrology, largely in support of quantum measurements. Relevant technologies include transition edge sensor (TES) bolometers, microwave kinetic inductance detectors (MKIDs), SQUID multiplexers, parametric amplifiers, silicon feedhorns, and metamaterial lenslet arrays.