I only read the last parts, starting from the chapter about induction, so take that into consideration.
The 'scratch work' sections are great, and this book did what other books didn't, it gave me a tactic for doing proofs. Other books show a lot of proofs and explain why the proofs are correct. That is great, but without a 'tool set' for working with proofs it is hard to know were to start when you are supposed to do them yourself. This is the only book I have read, also since, that do this deliberately and it gave me the foundations I needed to follow discrete math courses.