In this exhilarating new book, Brian Greene explores our most current understanding of the universe, its deepest laws of nature, and our continuing quest to know more. The Hidden Reality reveals how major developments in different branches of fundamental theoretical physics-relativistic, quantum, cosmological, unified, computational - have all led us to consider one or another variety of parallel universe. In some, they are separated from us by enormous stretches of space or time, in others they're hovering millimetres away, in others still the very notion of their location proves to be a concept beyond our reach. Most extraordinarily, Greene shows how all of these parallel universe proposals emerge unbidden from the mathematics of theories developed to explain conventional data and observations of the cosmos. This is a life-changing book that gives us a true sense of the astounding possibilities of modern scientific investigation.