Well, I guess one of the good books that i came across during last two years in SPA is……..THE TIMELESS WAY OF BUILDING by CHRISTOPHER ALEXANDER. And i think it’s better to go through these few pages from the book(the link ahead) than to hear its appreciation through my keyboard.
http://tal.cs.tu-berlin.de/lv/ss2005/seminar_ig/texte/ChrisAlex_11.5.05.pdf