Reality altering books.

I’ve read a lot of reality altering books lately.
I’m not talking about things like A Brief History of time, which is meant to alter your perceptions of the universe.

For instance, The Awakening seemed to put me in sort of a time warp for a day or so, and did the same thing to my friend. Granted, he was on mind altering substances at the time, but I was not.
The Metamorphosis put me in a dreamlike state for the weekend I read it.
I just read The Dilbert Future, and the last chapter screwed up my perception of motion and size in relation to perspective.

Are there any books you’ve read that screw up your perception of reality that weren’t meant to?

Yay! I get to be the first person to say Illuminatus!

Nothing was ever the same after that.