All of our empirical knowledge of stellar mass black holes comes from X-ray binary systems, where a black hole accretes from a companion star. In quiescent states, the faintness of the accretion flow allows us to perform dynamical studies of the companion stars and derive black hole masses. The faint light from the accretion flow is of considerable interest in its own right, however, as these objects provide a superb environment in which to study the astrophysics of low-luminosity accretion. Although such accretion flows are described as 'quiescent', they are observed to be violently variable. This variability provides a tool to study the structure of the accretion flow. I will describe how results from new coordinated multiwavelength observations allow us to test models for these quiescent accretion flows.