It isn't what we don't know that gives us trouble, it's what we know that ain't so.

God created man in His own image, says the Bible; philosophers reverse the process: they create God in theirs.

A witty saying proves nothing.

The books that the world calls immoral are books that show the world its own shame.

Books! I dunno if I ever told you this, but books are the greatest gift one person can give another.

They say a little knowledge is a dangerous thing, but it's not one half so bad as a lot of ignorance.

Knowing others is wisdom, knowing yourself is Enlightenment.

Know what you are talking about.

Knowing is not enough; we must apply. Willing is not enough; we must do.

Medicine is my lawful wife and literature my mistress; when I get tired of one, I spend the night with the other.

You can never learn less, you can only learn more.

A man who has never gone to school may steal a freight car; but if he has a university education, he may steal the whole railroad.

Most people have never learned that one of the main aims in life is to enjoy it.

If you can't explain it simply, you don't understand it well enough.

A little knowledge is a dangerous thing. So is a lot.

I am a part of everything that I have read.

Evil being the root of mystery, pain is the root of knowledge.

Education is our passport to the future, for tomorrow belongs to the people who prepare for it today.

If I have seen further it is by standing on the shoulders of Giants.

For a successful technology, reality must take precedence over public relations, for Nature cannot be fooled.

I cannot live without books.