This popular science book offers a glimpse into a plethora of extreme cosmic phenomena in which the theories of modern physics, particularly quantum mechanics and general relativity, play a key role. Despite their vastly different appearances, these cosmic phenomena have much in common: they are all powered by exotic stars - black holes, neutron stars and white dwarfs - collectively called compact objects. The book describes, in accessible language, the physics underlying these phenomena, the historical background that led to their discovery, and the various observational techniques used by astronomers for their exposure. The book contains many spectacular photographs taken with modern telescopes around the world and satellites of different space agencies, as well as illustrations specially prepared by the author to enhance the reading experience.