I've been trying to come up with a meaningful review, but I can only say that this book, along with the whole series, is the most perfect paranormal/urban fantasy/murder mystery I've read in a long while. I can only compare it to TJ Klune's Green Creek series, and just because of the wolves.

The Wolf at the Door is an exciting, angsty, suspenseful mystery with wolf shifters, a slightly awkward agent and his temporary partner who happens to be a wolf shifter himself. The story is engaging and captivating. The characters are far from perfect but very very lovable and fun. The mystery is definitely mysterious and we are kept on our toes the whole time. The world building is slow but it suits the story (throughout the whole series).

Copper might be one of my favourite main characters.  He's a complex person with heavy and substantial baggage, a chip on his shoulder, and an urge to prove himself competent and useful. But he's also smart, quick-thinking and a lot reckless. He's interpersonal skills are not the best and he's attmpts at romance need some work. Yet, I couldn't help but adore him.
Along with Oliver Park, his wolf shifter partner, they make an unlikely but very efficient (well, mostly) pair of investigators. Even though their friendship starts out haltingly because they're the first human-shifter partnership. And also because of Copper's mistrust, the bureau's mistreatment of wolves and their fledgling attraction.

Without spoiling anything, I just want to say that this is a really well-written book and series and it's definitely on my regular re-read list.

The narrator took a little but of getting used to, just because he's talking a bit faster than usual. However, I ended up liking him a lot.