  I present an elementary primer of black hole physics, including its general
relativity basis, all peppered with astrophysical illustrations. Following a
brief review of the process stellar collapse to a black hole, I discuss the
gravitational redshift, particle trajectories in gravitational fields, the
Schwarzschild and Kerr solutions to Einstein's equations, orbits in
Schwarzschild and in Kerr geometry, and the dragging of inertial frames. I
follow with a brief review of galactic X-ray binary systems with known black
holes, stressing the QPO phenomenon in particular.
  I then discuss the evidence from AGN for the existence of supermassive black
holes in galaxy nuclei, as well as evidence for such black holes in ordinary
galaxy nuclei. I use the free motion of gas parcels to illustrate aspects of
accretion disks around black holes, showing how to calculate energy efficiency
and surface emissivity of disks, and the rate of black hole spin-up. I recall
the primary methods for black hole mass determination, the correlation of black
hole mass with the stellar velocity dispersion of its neighborhood, and
implications for the origin of supermassive black holes. Finally, I consider
the formation of primordial black holes, and calculation of their mass spectrum
at present in the case of scale invariant primordial inhomogeneities.
