The Wolfen is one of the classics of werewolf literature and was turned into a movie sometime in the 1980's, if I recall correctly. I saw the movie, thought it pretty mediocre and was not interested in reading the book for a long time.
The basic premise of The Wolfen is that werewolves are not humans that can turn into wolves or the other way around. Rather, they are an intelligent species of the canine family that has been able to evolve and thrive unbeknownst to the race of Men. And they are predators, eating the lonely and the forgotten, those who will not be missed. Until they make an unexplained mistake and eat two police officers, causing the heroes of the novel to find out about them...
In addition to the relatively uninteresting concept of the werewolf (in my opinion), the novel does offer a tiny look into the life of a female police officer in the 1970's, when a woman as a detective was not such a common sight.
But the predictability of the story and the failings in storytelling at the aspects that bring this novel down. Overall, the story would have been better with a good editing, cutting away the awful repetition: show a scene from one perspective, then again from the Wolfen perspective and then again through a discussion between some of the characters as well as through the thoughts of some of the characters - then the same with the next "action" scene. The same is done with the description of being a woman police (the rarity and difficulties are repeated several times) and the relationship problems (also repeated with tiny new additions).
If you are willing to forgive the storytelling problems, the main story is relatively predictable. Still, it is better than the movie, so worth reading if you happen to be interested in werewolves.