Accretion in Black Hole X-ray Binaries

I will discuss the process of accretion and ejection in black hole X-ray binaries. Because stellar mass black holes are nearby and in binary systems, their masses can be estimated better than all but a handful of active galactic nuclei's black holes. Recent improvements in distance estimates from VLBI measurements and from Gaia now give them comparable distance uncertainties as well. I will emphasize how we can use variability information to understand these systems to get at the properties of the accreting black holes (e.g. spins and perhaps masses), and at the processes that cause jets to be produced in these systems. I will discuss how multi-wavelength data sets are essential for this work, and will also discuss how current and future projects across the wavelength range may enhance capabilities for studying all these topics.