Henri Bergson (1859-1941) was once the most famous philosopher in the world, but his reputation waned in the latter half of the 20th century. Barry Allen here makes the case for Bergson as a great philosopher, one whose thought has much to contribute to contemporary philosophical questions. Living in Time presents chapters on each of Bergson's four major works, explaining his theories of time, perception, memory, and panpsychic consciousness, his innovative concept of virtual existence, his objection to Darwin, his controversy with Einstein, his philosophy of creative evolution, and his social philosophy of closed and open society.

In particular Allen focusses on Bergson's powerful ideas on time. Classical arguments for determinism fallaciously apply spatial concepts to consciousness; once we take time seriously, which means acknowledging its reality as duration and its difference from space, Bergson showed that the arguments for determinism become insupportable. Bergson's ideas on time and evolution offer a comparison with Nietzsche, which Allen develops, exposing both philosophical concurrence and systematic difference. The book's conclusion discusses the question of Bergson and naturalism and summarizes the ontology of the virtual that emerges as a core part of Bergson's thought.