The Quarry by Iain Banks
Iain M Banks was pretty much my favourite SF author these days. So I was sad to hear of his illness a few months ago. I read one of his non-SF books (written under the name Iain Banks in case you're not up on that detail), The Bridge. I really didn't like it, but persevered to the end in case it got better. It didn't. I started another one, I forget which, and abandoned it.
I bought The Quarry, a non-SF book, as a tribute to him, and was pleasantly surprised to find that I enjoyed it. The main character's father is dying of cancer and so I couldn't help but read it with the assumption that he knew he was dying as he wrote it. Indeed when I researched it I found out that this appeared to be true (via Wikipedia).
I'm not really good at book reviews, so go follow the links above to get an idea what it's about. There's strong language and philosophising but I think you'll find it will make you think.