My oldest son enjoyed this book and checked it out of the library at least 5 times a few years ago. I was browsing at the library the other day and happened to see it and brought it home for my youngest. He's loving this book. He stayed up half the night the first night reading it and he has plans to do a bunch of experiments that it has in it. He has also been asking us a ton of riddles and silly questions like "If vegetarians are people who eat vegetables, what exactly are humanitarians?". He's already made plans to either purchase the book or check it out of the library a bunch more times like his brother did. I need to check and see if there is a Big Book of Girl Stuff for the girl.