Although I've known of C. J. Box for years, this is the first of his books I've actually read. It's the third in the series and I chose it because it happened to be a random unread book on my shelves. I think it would probably be better to start from the beginning of the series, as some important events that happened in earlier books are mentioned here. But I really enjoyed finally becoming acquainted with the author's work.
In an epigraph to the novel, we learn that"winterkill" is defined as "to kill (as a plant or animal) by, or to die as the result of, exposure to winter weather conditions. There are quite a few deaths in this story, and it is winter, but Box is expanding the meaning of this term a bit to cover most of them, some of which could have happened in any season at all.
I really enjoyed Box's gift for rendering the Wyoming landscape--and the Wyoming winter--so vividly. His protagonist, game warden Joe Pickett, spends a lot of time traversing wide expanses of wild land, and it's never boring. His work reminds me a bit of Tony Hillerman in his descriptions of the Southwest.
Another enjoyable aspect of the book, and presumably the series, is that Pickett's roaming is counterbalanced by his home life with his wife and daughters. They are portrayed lovingly and with an eye to their individual aspirations. A couple of the women outside of this sphere are portrayed in a black and white, good and evil sort of way, where I think they could have been painted a little more complexly. Box is capable of it, as seen in the shadowy character Nate Romanowski, who pops up part way through the novel. But it's a small quibble. I look forward to reading more of the series.