Gaitskill and Rand

I'm reading and really digging Two Girls Fat and Thin, though I have reservations about the opening section. One of the coolest lines from the book, I thought, was "Every loneliness is a pinnacle"...until I realized that it was an Ayn Rand quote. Is this such a well known quote that she doesn't have to give Rand credit? I'm Rand-ignorant, so please, any Rand enthusiasts, help me out.

I've never had much interest in Rand's work but Two Girls Fat and Thin satirizes it. I'll read on past the heroine's childhood sketches and see if I still like it.