I had to read this for a course I took It was an introduction to internal auditing. It was interesting enough, I would recommended it for anyone who wants an intro into internal auditing but I would also recommend it for anyone who has to do business process analysis. It makes you think about things that you might otherwise miss, risks you may never have considered. Other than that, I'm just glad class is over. Now onto real books.
This is the best general overview of internal audit that I have read. A great starting point before delving into more detailed applications of the principles.