Everyone read Judy Blume as a kid/pre-teen; I have always thought of her as more faux-controversial than actually controversial, because it was always through public school that her books crossed my path, and we actually read some of them (like the truly awful Frecklejuice) as a class assignment. The rest I sought out on my own -- even as a kid I realized they were dated as they all had a very crusty, 70s vibe that I found weird. So much had changed for women in girls in the era of Blume's career, so even a book about menstruation could feel outdated (Pads on belts? Whaaa...?) But despite those limitations, there is something so incredibly timeless about them and her ability to capture the emotional tenor of early adolescence is remarkable.
The problem with a prolific author like Judy Blume is that she made such a name for herself as an author for children that her adult books easily found their ways into classrooms and junior high libraries -- thus, my fling with Summer Sisters, which was surreptitiously passed around and dog-eared by my group of friends, for whom it was the pinnacle of erotic fiction (we did not try very hard to seek out erotic fiction). As an adult, this is still one of my favorite guilty pleasure books; it was clearly written to be read at the beach, and as heavy as the sexual content is, I think it's one of the best books on female friendship ever written.
If you haven't taken the time to keep up with Judy Blume since you were 13, read this dialogue between Blume and a young writer she has a had a tremendous influence on, Lena Dunham.