I find this most fascinating.
HUMAN EVENTS ONLINE :: Ten Most Harmful Books of the 19th and 20th Centuries
I hadn't ever really thought of books in terms of degree of harmfullness. I haven't read any of the books on the list, though I've heard of most of them. Maybe I should read some of these sometime. I'm sure on the surface most of these books seem very harmless if not down right peaceful. But the devil too works in mysterious ways.
For now just remember that, "repetitions is the key to learning... and brain washing".