Atlas Shrugged -- My Senior Year English teacher made us study that book in extreme detail. We spent most of a year on this book and it was probably the single most useful thing I learned in highschool. The ideas in that book just sunk into my core; without me even knowing it this excellent teacher had grounded me in a lifelong Libertarian outlook and undid all of the PC, revisionist, Marxist programming the schools had stuck in my head for the previous 16 years.