Anyway I would say that a book can trigger a change of perspective on a particular aspect of your life:
'4-hour workweek' - Tim Ferriss (on lifestyle)
'Get Things Done' - David Allen (on organization and productivity)
'The Way of the Superior Man' - David Deida (on relationships)
'The prince' - Machiavelli' (on business and strategy)
'The little prince' - Antoine de Saint-Exupéry (on meaning of life)
'The Feynman Lectures on Physics' - Richard Feynman' (to remember you to be humble)
A lot of other books had broaden my perspective of life even if they weren't enough to trigger a change. That list would be immense.