A nice tip from ArchDaily on 25 good reads about architecture. The classic Vitruvius 10 books about architecture, is one of the most influential architecture books of all time and is readable on the link below. Le Corbusier, Aldo Rossi and Louis Sullivan along with several others famous architects are also represented by books in the following link. Good for the one who wants to read more about architecture and the thoughts behind it.
Picture and link from ArchDaily: 25 Free Architecture Books You Can Read Online | ArchDaily.