Over the past 6 years, we have been engaged in an
extensive program of multiwavelength observations of transient
galactic X-ray binary systems.  Dynamical mass measurements show
that many of these systems contain compact objects with masses
greater than the upper limit for neutron stars - these systems
are sometimes referred to as "Dynamically Confirmed Black
Hole Candidates" or as "microquasars".  Detailed study of accretion
flows onto microquasars holds the promise of identifying and studying
strong-field relativistic effects.  These effects are easier
to study in microquasars than in quasars and AGN, since the
former have larger fluxes and more accessible variability
timescales.   I will present X-ray data from the Rossi X-ray
Timing Explorer along with optical and infrared data from our
ground-based monitoring program, and show how such multiwavelength
studies have revealed new phenomena and constraints in these
relativistic accretion flows.