This is day 5 of Bout of Books, and the challenge is all about cover colors! Basically, pick a color, or colors, and find at least 4 books whose covers match! You can find more information on this challenge here.
I picked covers with a lot of blues on them. Here is Charlie Bone and the Beast, Star Wars: The Swarm War, Last Wool and Testament, and Letters of E.B. White (without the dust jacket, as I don't have the dust jacket).