Read about the end of the Production Code in Hollywood, the films in the years immediately prior to it, and the impact of Bonnie & Clyde on the box-office, its use of violence, a new level of ambiguity in sexual psychology, and how free and casual both that film and The Graduate seem to be in light of the restrictions of the films made under the self-regulations of the Production Code. I recommend Hollywood Cinema by Richard Maltby. It's an expensive book, so don't buy it; borrow it from a library. Good academic databases should stock it at least once, in some form or another. Needless to say, The Graduate is, or can be seen as, an embodiment of the adolescent angst felt deeply by the baby boom generation, and its feel-good rebellious ending was quite impacting.

I really, really like The Graduate. It's still very refreshing today, I think. The soundtrack, Hoffmann's performance and the said ending hit all the right chords for me.