I read this last night and, yes, it is a quick read.
It gets straight to the point. No psychobabble and no need to wonder if the author really knows what it's like to have a tough life. He was homeless, a criminal, bad start in life, the whole lot but he still turned his life around and managed to help many others in the process (the Big Issue, for instance). He is helping us through this book too.
I would thoroughly recommend it. Mine came from the library, but I will buy my own copy now and dip into it (can easily be kept in my handbag) whenever I feel the need for an attitude adjustment. There are several people in my circle I also wish to purchase a copy for.