You're not supossed to judge by the cover...

Initial Investigation:
Cover 1: The focal point of this cover is a blonde teenage girl sitting in what appears to be a garden. Her red shirt draws the viewers eye towards her. She is looking down to her side and appears to be deep in thought or possibly sad. The font of the title is not that large and is written in yellow which makes it blend in with the foliage. The cover includes that the book was a "Man Booker Prize Finalist" and has a review from The New York Times. The review describes the book as "melancholy and alarming" with the purpose of highlighting the main moods of the novel.
Cover 2: The cover features a bright yellow background which creates a sense of lightheartedness and warmth. A girl, wearing all blue, is included who seems to be turning and running away due to the blurriness of her figure. It is possible that she was just "let go" in reference to the title of the book which is displayed quite largely. The authors name, Kazuo Ishiguro, is displayed even larger. It also includes mention of the book being a Top Ten Bestseller, the Man Booker Prize, and a review from the Observer.
Cover 3: This cover pictures a small boat tied to a post in a possibly deserted body of water. There are no ripples in the water which makes it seem very calm. There is nothing living featured in this cover which creates a sense of isolation or alienation from human society. The background has an odd yellow hue which does not seem natural or safe. The font of the title and authors name are large and centered and there is mention to the Man Booker Prize and a review from Time.
Cover 4: This cover contains a childlike drawing of the human organs. The outline of the body seems to be made from barb wire which creates an eerie and dangerous tone. The  background is two shades of grey which helps contribute to the eerie tone. There are faint trees in the background which may be referring to the dreadful woods from the book. Mismatched font is used to write the authors name and title, which highlights the childlike aspect of this cover.

Similarities and Differences:
Cover 1 and 2 both feature a female, which can be deduced to being the main character of the book. Covers 2 and 3 both use the color yellow as the main background color though they create very different emotions due to their hues. Covers 3 and 4 do not include any people, creating a creepy sense of isolation.

A little closer look: Covers 1 and 2:
When viewing these images, the first thing I notice is a girl as a main feature. I would suspect that these women are the main characters in the prescribed book, though they are portrayed differently. In the first cover, the blonde woman is sitting very still in a lush garden. I assume that this could be one of the many well manicured gardens surrounding Hailsham. Because of her sideways gaze, she appears to be longing for something. She seems very somber or possibly depressed. The first words I think of when I view this are "alone" and "escaping." She seems like she has escaped reality and has found a secret haven to hide in. To me, it seems like she wanted to be alone.
When viewing the second cover, I think of the words "running," and "child." The word running is similar to the word escaping, used to describe Cover 1, but "escaping" has a more negative and serious tone.  Cover 2 makes me think of a group of kids who are playing a game, possibly hide and seek, and the "seeker" just started counting so all the "hiders" must run. The bright yellow background and blue clothing add to this lighthearted feeling.

If I hadn't read the novel, the first cover would make me think about life during the 70's. This way seem like a stretch but the girl's long flowing hair, long skirt, and red blouse appear hippie-esk to me. Based on her setting, she seems to be very in touch with her natural side. If I hadn't read the book and was viewing the second cover, I would assume the girl depicted is much younger than in the first cover. Her body language appears she is playing, or running, actions common of children. I would also assume that the girl is possibly Asian. This is because of the author's name printed largely across her and her hair cut.

Cover 1 is most likely from the perspective of someone outside of Hailsham. I believe this because everyone who lives inside of Hailsham does not reveal their true emotions about how they feel about their situation. Therefore, this girl would not be caught dead looking sad about her perfect-Hailsham life. Cover 2 is most likely from the perspective of a Guardian inside Hailsham. A Guardian could be found watching the children play in the fields. From a Guardians perspective, the children are ignorant to their situation and play like normal kids.

Cover 1, based on the artwork, makes me believe a woman wrote the book. Its possible that the somber mood the lonely girl creates has to do with a relationship with a significant other. I typically associate love novels with female authors. Since this is not explicit, it is also a mystery. I believe anyone interested in romance or in mysteries, specifically woman would be interested in reading this book based on the cover. Because the woman featured on the cover is blonde, someone from American or European decent might associate closer with her and be more likely to read it, as well. Cover 2, could have been written by either a male or female. The cover is fairly gender neutral and the bright color would attract anyone's eyes towards it. Because the woman on the cover has black hair, someone outside of the American/European decent group would also be likely to read this book. Therefore, Cover 2 might reach a wider audience.