It isn't what you have, or who you are, or where you are, or what you are doing that makes you happy or unhappy. It is what you think about.

Born into poverty on a farm in Missouri he was the author of How to Win Friends and Influence People (1936) a massive bestseller that remains popular today. He also wrote How to Stop Worrying and Start Living (1948) Lincoln the Unknown (1932) and several other books.