Loved the illustrations and colour palette in this one. My three year old was really interested by the somewhat surreal images that have the girl walking in and out of the books. I think for a book about books, which usually really struggle, it worked well. I loved the idea of the parents telling the kid she was allowed to read whatever books she could reach, and then her immediately climbing up the entire bookshelf to reach them all.
Bottom line: This might be a 3 in terms of picture books overall, with the images pushing it to a 3.5. But because I'm always looking for books about books or that celebrate reading, and since most of them are so terrible, I'm giving this a 4 because for that genre, it's excellent!