We are obsessed with the multiverse. From blockbuster movies Doctor Strange in the Multiverse of Madness and Everything, Everywhere, All at Once to television’s The Man in the High Castle and Rick and Morty, the idea that there could be an infinite number of universes holding an infinite number of possibilities captivates us. And this fascination is not new – the fascination with these repetitions dates back to the philosophers of ancient Greece. In The Allure of the Multiverse, physicist Paul Halpern examines the theory of the universe we can’t seem to let go; in an infinite universe, finite components are bound to repeat their patterns again and again. Halpern traces the multiverse from the ancient Greek debate over cosmic building blocks, to German philosopher Friedrich Nietzsche’s imagined eternal repetition of all events and lives in time, to Albert Einstein’s special and general theories of relativity opening the door to the fourth dimension (another way of enlarging reality). All these ideas together culminated in Princeton graduate student Hugh Everett’s ‘Many Words Interpretation,’ in which all possibilities of existence simultaneously exist. That imaginative idea led to numerous other multiverse notions, including the idea that the universe might be a collection of ‘bubble universes,’ each inflated from the primordial stuff of the cosmos. Yet the prospect of such a maddening labyrinth of parallel realities has led other researchers to propose alternatives, such as bouncing universes in multiple dimensions, that are every bit as perplexing. An epic through physics’ history, The Allure of the Multiverse explores one of physics’ most controversial – yet most persistent – ideas