The books are all stand-alone novels. However, many people do prefer to read the Paul Madriani books in chronological order. The only three that are part of a set, a trilogy, are The Guardian of Lies, The Rule of Nine and Trader of Secrets. I would recommend reading those three in order. Of course, there are three books that are outside the Madriani series: The Simeon Chamber, The List and Critical Mass.
