Daylighting, a controlled architectural tool that influences users' perception and behavior, in university libraries and their influences on users' preference and satisfaction was examined in this study. The effects of daylighting in coordination with visual comfort, on university library users were measured in relation to four environmental processes, namely privacy, personal space, territoriality, and crowding. It was found that daylight and four environmental processes are related. It is believed that the consideration of this relationship will encourage students to use their libraries fully as an essential component of university education and campus life. (Contains 8 figures.)