Explore the theoretical physics concepts surrounding the destruction of Fermi surfaces in this comprehensive lecture delivered at the BSS Physics School. Delve into the fundamental question of how Fermi surfaces can cease to exist, examining the various mechanisms and theoretical frameworks that govern these quantum phase transitions. Learn about the different pathways through which a Fermi surface might "die" or disappear, including discussions of quantum critical points, non-Fermi liquid behavior, and exotic phases of matter. Gain insights into advanced condensed matter physics concepts as the lecturer presents theoretical models and experimental observations that illuminate the complex physics of electronic systems undergoing Fermi surface reconstruction or destruction.