A monumental work on the flow of time, from the universe’s creation to “now,” by the best-selling author ofPhysics for Future Presidents.

“Now” is a simple concept—you’re reading this sentence now. Yet a real definition of “now” has eluded even the great Einstein. We know that time stretches and is affected by gravity and velocity. Yet, as eminent physicist Richard A. Muller points out, it is only today that we have all the physics at hand—relativity, entropy, entanglement, antimatter, and the Big Bang—to explain the flow of time. With these building blocks in place, Muller reaches a startling conclusion: our expanding universe is continuously creating not only new space but also new time. The front edge of this new time is what we call “now,” and this moment is truly unique—it is the only moment in which we can exercise our free will. Muller’s thought-provoking vision is a powerful counter to established theories in science and philosophy, and his arguments will spark major debate about the most fundamental assumptions of our universe.