What if C S Lewis, instead of honing his writing skills, watched lots of Shrek and Hoodwinked movies? I think you would end up with a book with Amazing potential that falls well short of the mark, which is exactly what The Land of Stories: The Wishing Spell is.
I could not read beyond, "She had a huge, caring heart and loved her kids more than anything else in the world." on page 36. It wasn't the first time I almost put it down for its poor editing. I almost did a few pages earlier then the reader is told that the children's mother lost her husband as if it were new information, because we could not have made that leap on our own simply from reading in the previous chapter that the children's father had died.
The children themselves are stereotypes. The girl is a book worm that pays attention in class, the boy sleeps in class, doesn't care about school, but by the sheer power of his being male, he has it all over his sister when it comes to getting the right answers or creative inturpretation.
It looks like no fact checking was done, The children are in a high enough grade to all be expected to read chapters from their text, and talk about subtext and metaphor, but they are studying fairy tales (Pre-K to Kindergarden). And the class (all but the one girl) suffer through it like hard school work.
If it was bad writing throughout I wouldn't bother talking about it. But the story-telling overall is very good. It is well paced, it keeps you engaged and has all of the potential for being a great book, had someone with a little experience gone over it with a red pen and helped the young author revise and clean it up.