 Black hole thermodynamics and results concerning quantum fields in the presence of strong gravitational fields more generally are without a doubt the most widely accepted, most deeply trusted set of conclusions in theoretical physics in which our current best, deepest theories—general relativity and quantum field theory—work together in seemingly fruitful harmony. Indeed, that black holes possess a physical temperature and entropy, and correlatively that there is a hitherto unsuspected and profound connection among gravity, quantum field theory and thermodynamics, is now as widely accepted an idea in theoretical physics as an idea with no direct empirical substantiation can be. As such, the study of black hole thermodynamics prima facie holds out the most promise for guidance in our search for a deeper theory of quantum gravity, in which the two would be intimately combined in a unified account of all known physical phenomena, from the behavior of quarks at the scale of 10-17 cm, to the cosmological structure of superclusters of galaxies at the scale of 1032 cm. (See the entry  Quantum Gravity.)  What is not widely shared is the vision of the path that this guidance purportedly shows us. 