These proceedings on a NATO Advanced Research Worshop on White Dwarfs is a reference source, not only on the specific field of the physics of white dwarfs, but also for astronomy in general. A wide variety of astrophysical problems are discussed in the book, ranging from stellar evolution, physics and chemistry of white dwarf atmospheres, stellar pulsation, physics of degenerate matter, binary systems and accretion processes, structure of our galaxy, extragalactic astrophysics and cosmology. The book presents the status of the field of white dwarf research in the early-21st century, and presents the findings of International White Dwarf meetings. Moreover, it provides guidelines for future research in this field and is suitable as a textbook for Master and PhD level students and young researchers approaching the field for the first time.