I got this on the suggestion of Malcolm Ocean (http://malcolmocean.com/), and it is probably the most inspiring thing I have ever read. Marshall first describes the loneliness of greatness in such haunting terms that I was brought to tears, but stays determined that this is indeed a worthwhile cause. The rest of the book is fantastically good advice about how to do just that.
Yes, as other reviews have said, the editing is sloppy, and often times there is is extensive amounts of the same information entirely copied and pasted, but the information contained in this book more than makes up for it. Give it a try, and push through. You won't regret it.