Ulysses by James Joyce, though that book pretty much prides itself on being unreadable so maybe that doesn't count.
I'll also put forward LOTR as an extremely difficult read that I never finished. I have a ton of respect for the man, I mean he created a really awesome world and he used his talents as a linguist to create an entire language for it, but...I just don't think he was much of a writer. He didn't have a sense of pacing, and he spent waaaayyyy too much time on describing things.
I'll also put forward LOTR as an extremely difficult read that I never finished. I have a ton of respect for the man, I mean he created a really awesome world and he used his talents as a linguist to create an entire language for it, but...I just don't think he was much of a writer. He didn't have a sense of pacing, and he spent waaaayyyy too much time on describing things.