This is the first in an urban fantasy series by John Levitt. It has a lot of the "normal" urban fantasy elements... people with some amount of magic ability that are unknown to the general population and they have some way of policing themselves.
The main character, Mason, has a "pet" sort-of-dog (Lou) that is somehow tied to his magical talents. The "pets" (Ifrits) are rare and something that only a few practitioners have.
We start out with someone or something trying to kill Mason. He, of course, manages to escape with help from Lou. After some investigating it turns out that another practitioner has been stealing power from others and is getting up to all kinds of mischief. Mason then has to stop him.
All in all it's a pretty decent book. Not up there with my all time favorites in the genre, but still good.