Gertrude Stein
I do not consider myself a Gertrude Stein expert by any stretch of the imagination as I tend to be at a loss for meaning, but this is what I like about her writing: I can only barely figure most of it out.
I have only read a few of her works. But in terms of her avant-garde use of language and metaphors, she is wonderfully complex and prolific. She is difficult to teach to undergraduates, who usually hate her. But as I stress to them, in order to appreciate her, you have to approach her on her terms, which is quite difficult for an 18 year old.
If you only read on thing of her's, read Tender Buttons (1912). You can download the entire book for free from the Gutenberg Project (http://www.gutenberg.org/etext/15396). “Roast Beef,” the first selection, is probably the coolest piece of writing I have ever read. It is perfect. But what does it mean? I have no idea.