Subtitled "Useful Scripts That Solve Difficult Problems", I was hoping to find a good collection of idiomatic scripts that I could recommend to folks getting started with Ruby. That's not really what I found though.
The book contains 58 scripts which represent a fairly wide swath of problems, but most of the programs are so short that they don't really show good, idiomatic Ruby. I question why some of the scripts are included (e.g., adding a user to a linux system — writing an wrapper around useradd doesn't seem useful, even as an exercise).
I'm not saying that a reader won't learn something from this book, but I don't think it would be a good first or second book on Ruby. If you're already a rubyist and you're looking for a book with some good ideas, this might be a good book to pick up.