This book is a history of how it came to be that our best physical theories of particles, gravity, and spacetime are theories of the vacuum, of empty space. Today, physicists calculate “vacuum expectation values,” predict the influence of “vacuum fluctuations,” and describe universes and black holes composed of dynamic, yet empty, spacetime. More than this, vacuum physics seems paradoxical. Physicists depict the vacuum as by turns placid and roiling; as a rippling sheet and a crashing sea. More than Nothing provides new interpretations of seminal advances in the history of relativistic quantum theory, including Paul Dirac’s positron theory and Richard Feynman’s and Julian Schwinger’s Quantum Electrodynamics. It provides sustained analysis of understudied figures, including John Wheeler’s geometrodynamics, Roger Penrose’s diagrammatic methods, and Sidney Coleman’s false vacuum. These studies analyze physicists’ diverse interests. This reveals surprising connections between positron theory and mathematical beauty; between fluctuations and Marxian philosophy; between the psychology of “impossible objects” and drawings of black holes; and between symmetry breaking and science fiction. The development of the physics of the vacuum was inseparable from the development of aesthetics, art, psychology, fiction—from culture. By analyzing scientific practice—as documented in notes, correspondence, drawings, laboratory notebooks, and published material—this book shows that physicists chose to center the vacuum because of its utility. Over and again, theorists found the vacuum useful.