We are developing superconducting electronics for applications in the measurement of electromagnetic signals. Our main focus is on the development of superconducting quantum interference device (SQUID) circuits to multiplex signals from superconducting microcalorimeters and bolometers. SQUID multiplexers are a practical requirement for the successful deployment of large-format cryogenic detector arrays for x-ray microanalysis and x-ray through millimeter-wave astronomy. We are also investigating other novel directions including the SQUID operational amplifier and the development of susceptometers for magnetic calorimeters. Research opportunities involve improving the noise and bandwidth of these devices, developing novel microwave reflectometer readout techniques for arrays of non-hysteretic rf-SQUIDS, fabricating SQUID circuits in our state-of-the-art superconducting fabrication facility, developing high-performance room-temperature electronics to drive our superconducting circuits, and exploring the device physics of SQUID circuits.