All massive galaxies host a supermassive black hole at their centers. Sufficient gas falling onto the
black hole creates a quasar that is dramatically brighter than its host galaxy; in fact, quasars are the
most luminous persistently emitting objects in the Universe. While the infalling gas powers the
quasar, the light it emits can, in turn, power an outflow that can be observed in the rest-frame UV
spectra. However, despite more than 50 years of study, the physical properties of quasar winds,
including fundamentals like the location of the outflow and the wind's potential for influencing
galaxy evolution, are largely unmeasured.

We pioneered the novel spectral synthesis software SimBAL, which uses forward modeling and a
Bayesian calibration to extract the physical conditions of the BALQ wind. Using SimBAL, we are
learning about the properties of winds, and the demographics of the winds is revealing aspects of the
quasar central engine. In this talk, I will highlight what we have learned, and describe some of our
future investigations.