Professor Greene gives an excellent introduction to the world of breakthrough science, how it often occurs by reconciling conflicts between two successful but mutually incompatible theories. For example, Einstein reconciled Newton's Mechanics and Maxwellian Electromagnetics with his Special Theory of Relativity. The current Big Question in the physical sciences now is how to obtain a theory akin to "quantum gravity" - i.e., how to reconcile Quantum Mechanics with General Relativity.  The book motivates this topic very well, then proceeds to give a very intuitive yet accurate account of the basics of String Theory. Often science journalists are good at metaphor and analogies but do so at the risk of misleading the reader. Because Professor Greene is a leading researcher in the field, he avoids that trap.  However, when explaining more recent aspects of the theory, which are more complex and speculative than the basic "elegant" foundation, the book loses clarity.  Perhaps it is because the findings are too new, and the scientists themselves still don't really understand the details well enough to explain them to others. Regardless, for understanding the nuances (albeit not the details) of the latest developments of string theory watch the Nova production by the same name, which is also narrated by the author, and which covers recent progress in the theory that is either not in the book at all or is not explained as well in the book. Although it falls short of explaining the entire theory as well as it introduces it, it is nonetheless the best book available now that is accurate yet accessible to the non-scientist reader.