I read this book because I enjoyed the movie. To illustrate why I didn't like this book very much, I guess I should go over why I liked the movie.
I liked the movie mostly because the idea was a good one. Villains trapped on an island with their children who didn't do anything to deserve incarceration? That's an incredible idea. It was made more interesting by the fact that the children must have been born on the island. I mean, the villains were imprisoned for twenty years, but the kids were only about sixteen. The other thing I liked about the film was the acting. Sure, sometimes the side characters felt forced, but the four principle characters were played by very good actors. I also liked the moment when Lonnie was surprised and heartbroken to learn that the villain kids were not loved by their parents. Disney's Descendants wasn't what I'd call a good movie. A lot of the plot points were really stupid and the parents didn't seem like the evil villains we were asked to believe they were, but the idea was a really good one.
So why didn't I like the book? Well, they didn't seem to be in bad enough shape. In spite of their impeccably fashionable costumes, in the 'Rotten to the Core' song we get a decent glimpse of how much of a slum the island is. There are people sleeping in little more then warehouses. There are people who seem like good people just trying to get by (that the four main characters victimize.) The MCs don't appear to belong with their fashionable clothes, and during one of Evie's verses she's standing among a bunch of beautiful like-new scarves that obviously don't belong in the scene. But we still get an idea of the poverty and suffering on the island. In the book, the villains are not scrounging for food or suffering for lack of clothing. They only receive the leftovers that Auradon doesn't want, but there is still more than enough food. The villains even care enough to give their kids schooling (in the arts of being evil, but honestly I didn't think there would be a school at all.) Given the fact that we are expected to believe that the villains don't care about their kids, it seems stupid that they'd care to make them go to school. I feel like they'd just expect their kids to learn their wickedness by watching them, but why would they go through the effort of enforcing school for children they didn't care about?
I am also rather skeptical about an island full of villains electing anyone, even Maleficent, to be their leader. If they're all as self-serving and terrifying as we're led to believe that they are, then none of them would want anyone but themselves to be the leader, though they might bow to the scariest one's demands, I don't think they'd actively call them leaders.
The other problem with this was that Cruella was the cruellest parent (at least that we've seen) on the island. She neglects Carlos, and forces him to clean the house and take care of her and her clothes. She treats him like a slave. And in the film Carlos was the only one who said actually expressed interest in going to Auradon--or rather, interest in getting away from the isle and his mother. We see Jafar, Evil Queen and Maleficent saying mean and nasty things to their kids, but they never do more then speak nastily to them. I know that both the book and the movie are for kids so I can understand that they didn't want to scare the targeted audience with descriptions of parental abuse, but c'mon. These are evil villains who we're asked to believe don't care about their kids, and don't care about anything but themselves. We're told that these villains are the worst in the world, but we're never really shown it. Evie's mother even seems to care about her a bit--mostly because she's beautiful, but still.
I also thought that the four characters didn't altogether match the impression we'd gotten of them in the movie. The movie starts with the four of them terrorizing the less evil citizens of the island, but, while the book ends with the author saying that the characters ran off to terrorize the others on the island, only Mal and Jay had ever done that before. Carlos was bullied by the other children as well as his mother, and it seems highly unlikely that he would just start doing the bullying. Evie seems to have a bit too much propensity for good in her. She wasn't taught to be honest, but even though she lies, her first instinct seems to be to help others (like Carlos,) and her line in Rotten to the Core ("I broke your heart? I made you hurt?") doesn't seem to fit her at all because she spent most of her life isolated, and she hadn't any experience breaking hearts even if she were disposed to do so. The four of them had only just become (almost) friends and I didn't really think that they would have been comfortable wreaking havoc together so soon after Mal decided to stop hating Evie (also, in the movie, Evie's not inviting Mal to her birthday party was mentioned in passing, as something that maybe bothered Mal a little bit over the years, but not something that had festered and caused her to attempt vengeance on Evie as it was portrayed in the book.) Because Mal and Jay were (almost) friends at the beginning of the book, and they were the trouble makers, they are the only ones who's behavior in the film matches their behavior in the book.
The author also should have watched a few more Disney films. I didn't find many errors, but the most egregious one was that Perdi and Pongo were complaining about having to pay four 101 college educations when they only had 99 puppies. They were dogs numbers 100 and 101 (and if you read the book there were only 97 puppies because there were 4 adult dogs, Pongo, Mrs. Pongo, Perdita and Perdita's mate.) Even the fact that the dogs were complaining about anything didn't fit with the world we were given in the film. Not with the way that Dude acted more or less like a normal dog, and no one treated him like a person. I also don't understand why Anastasia and Drizella (and their children) are on the island. Even if you disregard the sequels where Anastasia gets a happy ending, (not to mention Iago in the Aladdin sequels) Anastasia and Drizella are guilty of nothing more than bullying. Behavior we see from everyone in Auradon--from Audrey, daughter of Sleeping Beauty, to Chad, son of Cinderella, to the one science teacher who took Evie's mirror in the film. and none of those characters are sent to the Isle of the lost for their behavior. The last error that I was more inclined to forgive was that Doc said something about his son, Doug, when in the Descendants movie, Doug was Dopey's son.
I don't like very many of the Auradonian characters. In the film I liked Lonnie well enough, and in the Wicked World YouTube show I started to like Jane better, but I didn't really like Ben and Ben in the book is just as dull and uninteresting as in the film. I also found myself feeling rather annoyed with how stupid both Belle and Beast behaved. Beast seemed stupider, but Belle being a book-nerd, it was more obvious with her. No matter how I look at it in either movie or book, it's beyond stupid that someone would be crowned king while his parents were still alive, while he was still in high school. It would make far more sense if they waited until he graduated high school, and maybe college.
Another problem with the book (and the movie, but it's more obvious in the book) is the question of who the villain kids' other parent is. Especially because Maleficent keeps telling Mal she's just as human, weak and good as her father. Um, Mal is sixteen and Maleficent has been imprisoned on the isle for twenty years. All of the characters parents must have both parents among the prisoners of the Isle, (and what good person would create a child with someone they consider evil.) After I watched the film I thought that it would have been good if we'd seen villain children with two different villains for parents. I mean, Jay and Mal already act like siblings, so why not make Mal's dad be Jafar and Jay's mom be Maleficent?
I will probably give Return to the Isle of the Lost a go, but after this book, I don't really expect to like it that much. And don't get me wrong, the Descendants movie isn't great. It's a corny, half baked plot, and poorly created world, with (mostly) good actors, but a really good original idea. I liked the movie because it led me to imagine what (at least in my head) seems like a much better story using the same idea of imprisoned villains, not because it was a good film. The book didn't add anything to the poorly created world and, if anything, it took away some of the things that had been left to the imagination, that could have been better. The plot was even worse than the movie, and the characters didn't seem to fit well with what we'd seen of them in the film.