This is a kind of tame Jack Sparrow meets Sherlock Holmes kind of book. But that description doesn't do the thing enough justice. What it does is draw you into the world it occupies. You might be sat in your 21st century city, but really feel the oppression of 17th century London - or Marrakech for that matter. 3rd in a series, but I don't think you have to read the rest to know what's going on here.