Considering that Black Dog is Stephen Booth's first novel, and that it's a mystery series opener, it's really quite good.
As the book opens, Ben Cooper of the Edendale police (in the Peak District of England) is involved in the case of a missing teenaged girl, Laura Vernon. According to her parents, she was a wonderful child, interested in school and horses, and would never just up and run away. The police force is giving its all on this case, but the body is actually discovered by an elderly man, Harry Dickinson, and his dog, Jess, while out on a walk. He's interviewed by the police, but Cooper realizes that Dickinson's not telling everything he knows. But he's not the only one keeping secrets. It seems that many people in the small town of Edendale are keeping mum, hindering the investigation at every turn.
For a first novel in series, it's well done. The author goes to great lengths to introduce Ben Cooper, who is the son of a local police legend, and who lives at the family home, helping his brother take care of his ailing mother. Ben is also gearing up for promotion to sergeant, but Cooper joins the ranks of other UK angst-ridden detectives who carry an immense amount of emotional damage. He's also met his match in a new DC, Diane Fry (a very unlikable character), who is ambitious and has no scruples when it comes to getting what she wants. She has it in for Ben almost immediately, and their complex relationship is examined as the story progresses.
The book is a bit longer than it needed to be and while the end will catch you by surprise, it's a bit contrived. However, considering that it is the author's first book, I was impressed.
I'd definitely recommend it to fans of British police procedurals; cozy readers may find it a bit more complex than what they're used to reading. Overall -- a good start to a series which I plan to explore further.