Jack Williamson is one of the legends of science fiction writing and he is known for coining many terms in his fiction that are in general use these days, such as android, terraforming and genetic engineering. His enthusiasm with science fiction is also apparent in his so-called werewolf novel, Darker Than You Think (1940), in which the the plot and existence of shapeshifters is heavily based on genetics.
The protagonist is Will Barbee, a newspaper journalist who has been disappointed in his life when he was driven away from an anthropological research team. The story begins with him on an airport, waiting for the arrival of the said research team, most of them still his dear friends, from their expedition to Mongolia. Upon arrival, the researchers proclaim that they have important news to share, but before the leader of the team can say what he takes his time to say, he drops dead. And his sudden and mysterious death is only the beginning. Soon, the protagonist begins to have nightmares of himself turning into a wolf and other creatures and going after his once-dear friends.
Overall, the story is very straight-forward and offers no real surprises along the way. In fact, most of the revelations that Will Barbee encounters have been clear to the reader from the beginning and we read on, waiting for the protagonist to figure it all out. The problem is that, for the longest time, Will ignores his dreams and brushes the deaths of his friends away as mere coincidences, while still drinking himself silly in an attempt to forget those dreams.
The main problem in the story is the protagonist. It is clear that the author wants us to see how he is denying the reality of his situation, but when he eventually does realise what is happening he still refuses to make any serious attempt to stop it. Add to this the relatively predictable plot and heavy-handed repetition, and the whole ends up being merely an average read. For a werewolf enthusiast it is only of a passing interest, as the wolf form is only one of the many shapes the shapeshifters can transform into. Also, there are perhaps a little too many inexplicable fantastical elements in the plot, such as the shapeshifters' ability to walk through solid walls.