The book, "The Elegant Universe: Superstrings, Hidden Dimensions and the Quest of the Ultimate Theory,'' by Briane Greene, is an excellent survey of much of string theory. Several Scientific American articles focus on some recent developments: ``Explaining Everything,'' by Madhusree Mukerjee (January '96) covers the `second superstring revolution' of 1995; ``Black Holes and the Information Paradox,'' by Lenny Susskind (April '97) discusses some of the paradoxes of black holes in quantum mechanics, and their possible solution via string theory; ``The Universe's Unseen Dimensions,'' by Nema Arkani- Hamed, Savas Dimopoulos, and Gia Dvali (August '00) discusses the experimental signatures of extra dimensions and branes. One educational website is
http://www.theory.caltech.edu/people/jhs/strings/index.htm,
by John Schwarz. Another useful educational website is: http://theory.tifr.res.in/~mukhi/Physics/string.html, by Sunil
Mukhi.