The astrophysics of cool white dwarfs

Old, cool white dwarfs convey valuable information about the early history of our Galaxy. They have been used to determine the age of the Galactic disk, several open clusters and a globular cluster. We review the current understanding of the physics of cool white dwarfs, including their mass distribution, chemical evolution, and cooling. We also examine the role of white dwarfs as tracers of various stellar populations, both in terms of observational searches and theoretical models.