Part I: The Edge of Knowledge Chapter 1, "Tied Up With String", briefly introduces the conflicts between our current theories, and how they may be resolved. He introduces the building blocks of matter,
electrons and
quarks, and the forces that govern them.
Part II: The Dilemma of Space, Time, and the Quantum Chapter 2, "Space, Time, and the Eye of the Beholder" explains
Albert Einstein's
special relativity, which united
James Clerk Maxwell's
electrodynamics with
Galileo's
principle of relativity. Einstein established that
speed of light is a universal constant, and that the laws of physics are the same for all observers in relative motion. As a consequence,
Isaac Newton's absolute time and space were replaced by a dynamic
spacetime. Chapter 3, "Of Warps and Ripples", introduces Einstein's
general relativity, which resolved the conflict between Newton's theory of
gravity and special relativity. General relativity explains gravity as the curvature of spacetime. Chapter 4, "Microscopic Weirdness", introduces
quantum mechanics. Greene begins with
Max Planck's 1900 proposal that energy is absorbed and emitted in discrete units, or
quanta. In 1905, Einstein used quantum theory to explain the
photoelectric effect, the extraction of electrons from a metal by light. Greene uses the
double-slit experiment to illustrate
wave-particle duality of light.
Louis de Broglie extended this to include matter.
Werner Heisenberg's
uncertainty principle says that we cannot simultaneously know the position and velocity of a particle, and the more we know about one, the less we know about the other. Chapter 5, "The Need For a New Theory: General Relativity vs. Quantum Mechanics" explains the conflict between the two pillars of modern physics.
Part III: The Cosmic Symphony Chapter 6, "Nothing But Music: The Essentials of String Theory" offers a brief history of
string theory, starting with
Gabriele Veneziano's work on the
strong nuclear force. String theory replaces the conception of electrons and quarks as point particles with tiny, vibrating loops of string. One such vibration describes the properties predicted for the
graviton, the postulated quantum of gravity. Chapter 7, "The 'Super' in Superstrings discusses the importance of symmetry in physics, and the possibility of
supersymmetry. Chapter 8, "More Dimensions than Meets the Eye" discusses
Theodor Kaluza's proposed unification of
general relativity and electromagnetism, which required an extra dimension of space. The idea was elaborated on by the mathematician
Oskar Klein. Chapter 9, "The Smoking Gun: Experimental Signatures" discusses criticisms of string theory, namely that it has not yet yielded testable predictions. Greene explains how this may change in the near future.
Part IV: String Theory and the Fabric of Spacetime Chapter 10, "Quantum Geometry" discusses
Calabi-Yau spaces and their applications. Chapter 11, "Tearing the Fabric of Space" discusses Greene's own work in string theory, and how strings could repair tears in the fabric of space Chapter 12, "Beyond Strings: In Search of M-Theory" discusses the different versions of string theory, and how they might be pointing towards a single theory, mysteriously called
M-Theory. Chapter 13, "Black Holes: A String/ M-Theory Perspective" looks at mysteries of
black holes and how they might be resolved by string theory. Greene discusses
Stephen Hawking and
Jacob Bekenstein's discovery of
black hole thermodynamics and Hawking's discovery of
Hawking radiation. Chapter 14, "Reflections on Cosmology" gives an overview of the standard
Big Bang model and the refinements of
inflationary cosmology. String theory could answer questions such as whether the universe began with a
singularity.
Part V: Unification in the Twenty-First Century Chapter 15,"Prospects" looks at questions string theory might answer, such as the nature of space and time. He speculates about the future of the theory. ==Reception==