Moler's lab builds scanning SQUID microscopes -- magnetic-flux sensors cooled to cryogenic temperatures and scanned within microns of a sample -- to image supercurrents, vortices, and interfacial magnetism in unconventional superconductors and topological materials with sensitivity and spatial resolution that complements ensemble NV-diamond magnetometry (which reaches pT/√Hz via DEER/T1-type protocols) at a very different length and field scale.