Just a note, this book is not the first of the series! I love Patricia Briggs, but good heavens, her mix of series and short stories is confusing! If you go to her website, she has a "Mercyverse" timeline that is very helpful. Before reading this one, read "Moon Called" and then "Alpha and Omega" the short story, which can be found in the book titled "Shifting Shadows."
I was halfway through the Mercy Thompson series and was thinking, gee, I feel like I missed something! There were major events happening between novels that impacted the stories in a big way but only got a minor mention at the beginning of the book. Turns out there's this WHOLE OTHER SERIES running parallel to that one! Well, I finally caught up, and I'm so glad I did. The Mercy Thompson series feels more full knowing more about Bran's history, Charles, and his mate Anna. I think Anna's characterization is not nearly as strong and consistent as Mercy's or Charles', but it's still a great series and I love it's fast-paced combo of fantasy adventure, mystery, romance, and humor.