Let me preface all of this by stating that I am not usually a fan of self-help books. I know they help a lot of people, but I think most of them are filled with meaningless drivel that egomaniacs churn out in order to earn a book. This is why I was so blown away by The War of Art. Pressfield breaks down all motivational factors into one concept: resistance.
He explains how resistance is the force that keeps us from achieving our goals and is always out to ruin us. While Stephen Pressfield may be a little more spiritual than I am, I definitely agree that it's easier to get motivated when you put a name to what's holding you back. In this way, The War of Art has helped me like no book has ever helped me before and I honestly can't recommend it high enough.