Here is the updated essential guide to physics, an authoritative reference book and timeline that examines the foundations upon which all scientific knowledge rests. Without physics, everything else from astronomy to zoology would be meaningless conjecture. Our journey begins with the first attempts to understand reality, Mother Nature or as the ancient Greeks called it, physis. Follow the journey through history as great scientists, such as Thales, Galileo, Feynman, and many others, gradually unpick the fabric of the Universe revealing an array of fundamental forces, intangible particles and indestructible energy. Today, physics discoveries make headline news as we all grapple with the fresh mysteries of the Higgs boson, supersymmetry, and dark energy. The boundaries of physics are on the move once again. What new truths will be revealed next?