Carnegie, I was shocked to learn, is not the famed Carnegie who built Carnegie Hall. That was Andrew Carnegie, the famed steel magnate who certainly must have picked a great many roses from outside his window, because he made crazy amounts of money and then gave it all away to libraries and the arts and other philanthropic endeavors. I admire that Mr. Carnegie. He was rather how a Christian should work in the business world; there's no problem with making money, but it ought to be used to improve the lives of those less fortunate (or at the very least, those who work for the company) rather than simply making rich men and women wealthier. Simply amassing a fortune and hoarding it isn't Christian at all! But I digress...I don't even know if Carnegie was a religious man.
Anyway. So this Dale Carnegie is someone completely different. He's the author of How to Win Friends and Influence People, that massively popular guide to making yourself likeable. (I assume that's the content, anyway - I've never bothered to read it.) He changed his last name from Carnegay to the alternative spelling so that he would instantly gain that association with the famed philanthropist. That's clever marketing, to say the least. But then, it seems like the guy was pretty clever, overall. He picked his fair share of roses as well.