The premise of the series is that it's about Harry David Copperfield Dresden, who's a hard-boiled, wise-cracking
The story begins with Dresden brought in by the police department to help investigate a double murder. The plot then weaves between explanation of how magic works in this world, the investigation, complications (including the local mob), and a secondary plot involving a missing husband. As you would expect from this type of novel, Dresden gets beaten up, threatened, conked on the head multiple times, encounters femme fatales and resists them, and then eventually "solves" the plot, but not through cleverness but by simply being beaten up enough times.
One reviewer said that the Dresden novels are like Philip Marlowe but for the fantasy set. Jim Butcher is no Raymond Chandler, however, and his novels say much less about the human condition than Chandler's. Furthermore, there isn't as much pessimism, despite the fact that Dresden gets beaten up a lot. For instance, none of Dresden's females betrays him, while Chandler's females frequently get him into trouble or turn out to be the antagonist.
All in all, the book wasn't a waste of time, but pales compared to say, Altered Carbon or any of Chandler's novels. Nevertheless, suitable beach reading or vacation reading. Mildly recommended.