Side Jobs is a collection of short stories about characters from The Dresden Files series. Many of the stories have been published previously on the internet or in anthologies, so it’s not really new.
It’s kinda hard to describe the book because it contains a mix of stories of varying length and quality. Some are very weak and could be removed from the book at no loss. A couple are very good and show the characters they reference in a new light. One of the things with The Dresden Files series is it is all from the perspective of Harry, so you only know as much about other characters as Harry does. Some of these stories are told from other characters perspectives, so that quite literally changes your view point considerably.
If you are a Dresden fan I’m sure you’ll love it. If not, you will probably do well to avoid it.