Cataclysmic novae

The present state of understanding of the cause of stellar explosions in novae and related systems is examined. Two physical phenomena unique to cataclysmic variables are the occurrence of a cool, Roche-lobe filling binary component with a compact companion, and a rotationally supported accretion disc about this compact companion. The conceptual advances that cataclysmic variables have contributed to our understanding of these astrophysical structures, largely through tests based on eruption behaviour in dwarf novae and symbiotic variables, are reviewed. The distinctly different conditions of classical nova explosions are briefly explored.