"Physics of the Impossible" is a book by physicist Michio Kaku that explores concepts and technologies often considered science fiction. Kaku examines ideas like invisibility cloaks, teleportation, and time travel, discussing their feasibility based on current scientific understanding. The book categorizes these concepts into three classes: those that are impossible, those that are possible but not feasible with today's technology, and those that could be realized in the future. Kaku uses principles from quantum physics and theory of relativity to analyze these ideas, making complex topics accessible to a general audience.