Small Steps -- Louis Sachar
If someone other than Louis Sachar had written this book, I'd have called it mediocre.
But Louis Sachar DID write it. Not only did he write it, he wrote it as a companion/sequel to Holes. He was aiming high.
I hold Louis Sachar in very high esteem -- I adored the Sideways Stories books as a kid, and I've read and re-read Holes so many times that I know parts of it by heart. So I don't say this lightly. Small Steps was a crushing disappointment.
Holes is a jigsaw puzzle of a novel, multi-layered and multi-textured, level upon level of story and time and place, myth and meaning spiraling out from a simple beginning. Small Steps is simplistic and linear. It's just another teen novel. It isn't special. It's depressingly ordinary.
So if you haven't read Holes, do. If you have read Holes, just re-read it. Don't put yourself through the pain of reading a book that will never even come close to comparing to the original perfection.