This program is motivated by the recent observational insights concerning white dwarfs as individuals and as a population, based on the astrometry from Gaia and large photometric (Kepler, TESS, ZTF, VeraRubin) and spectroscopic (SDSS-V, DESI, WEAVE, 4MOST) surveys. Some of the questions that these data, combined with improved input physics and white dwarf models, will answer are: How does crystallization affect white dwarf cooling? How good is our understanding of convection, overshoot, and mixing in general? How good are the predictions of the low-frequency gravitational wave foreground and thermonuclear supernovae rates (SN Ia, Iax, Ca transients)? What is the nature of the recently discovered stellar remnants of thermonuclear supernova and/or their donors? What are the architectures of planetary systems that survive the metamorphosis of their host stars into white dwarfs, and what is their ultimate fate?