The August 2006 issue of Scientific American has an interesting account of

Fields Prize Winner Alain Connes and his development of noncommutative

geometry as an alternative to string theory ("Insights: the geometer of

particle physics"'; August 2006, pp 36-38). Via Google I found that Connes

has put a pdf of his book

Noncommutative geometry (Academic Press, 1994, ISBN 0-21-185860-X) on his

web site for free:

ftp://ftp.alainconnes.org/book94bigpdf.pdf