In 1957, Hugh Everett proposed a novel interpretation of quantum mechanics - a view that eventually became known as the many-worlds interpretation. This book presents Everett’s two landmark papers on the idea - “‘Relative State’ Formulation of Quantum Mechanics” and “The Theory of the Universal Wave Function” - as well as further discussion of the idea in papers from a number of other physicists: J. A. Wheeler, Bryce DeWitt, L. N. Cooper and D. Van Vechten, and Neill Graham.