Introduces the superstring theory that attempts to unite general relativity and quantum mechanics.

The edge of knowledge. Tied up with string --
The dilemma of space, time, and the quanta. Space, time, and the eye of the beholder ; Of warps and ripples ; Microscopic weirdness ; The need for a new theory : general relativity vs. quantum mechanics --
The cosmic symphony. Nothing but music : the essentials of superstring theory ; The "super" in superstrings ; More dimensions than meet the eye ; The smoking gun : experimental signatures --
String theory and the fabric of spacetime. Quantum geometry ; Tearing the fabric of space ; Beyond strings : in search of M-theory ; Black holes : a string/M-theory perspective ; Reflections on cosmology --
Unification in the twenty-first century. Prospects.