Napoleon Hill emerged out of a spiritual movement around the turn of the 20th century known as New Thought. There were a lot of books published in that tradition. Their core idea was that mental activity determines eventual physical reality. I find it interesting that this is a quintessentially American movement. There are traces of it all over the place to this day.

One of the great intellectual antecedents to such stuff is Emerson's Essays, which formulated an original modern American spirituality. Emerson is striking in how he seems to emerge out of nowhere. (Since nobody really does, I'd like to know more about his sources.) Anyone curious should read his essay "Self Reliance". It's a classic of entrepreneurial literature, though it doesn't talk about business. I hesitate to say this for fear of overselling it, but it's one of those rare pieces of writing that can change one's life (it changed mine).

As a surprising aside, Emerson was one of the biggest influences on Nietzsche.

I hate that book, actually. I started reading it, and I got the impression that it made the point that all you need is a burning desire, and you will succeed.

That is really not what I'm saying. Having a burning desire, convincing yourself that you want to succeed, etc, is by no means a guarantee of success, and implying that people who didn't succeed failed because "they didn't want it hard enough" seems rude, wrong, despicable even.

My point is that negative beliefs will reduce your chances of success (perhaps even to zero), and that fixing those beliefs can give you a higher chance of success.