When unlucky stars pass too close to massive black holes, they are torn apart by tidal forces. The return of bound, highly elliptical streams of stellar debris to pericenter initiates a chain of events that powers a luminous flare. These tidal disruption events (TDEs), once a theoretical curiosity, reach peak luminosities brighter than almost all supernova explosions, remain bright for months to years, and are discovered in ever-greater numbers by ongoing optical and X-ray surveys. In this talk, I will review the underlying scientific potential of TDEs as probes of massive black hole (MBH) demographics. I will discuss the idealized models that are used today to estimate MBH properties from TDEs, the ongoing challenge of understanding TDEs with predictive, first-principles hydrodynamic simulations, and the imminent revolution in TDE studies as eROSITA, VRO, and ULTRASAT expand our sample of TDEs (from its present-day value of ~100) by two orders of magnitude.