In theory, this book is an excellent idea. In practice, it is horrible. None of the songs make much sense; things happen without a single uniting idea behind them. It teaches redundancy and it keeps saying the same thing using different words (what?). On at least one page they mistake “you’re” for “your.” Terrible. The exercises also seem pointless. They give you multiple-choice questions, and four of the five choices are words that you don’t see in the song those questions are based on. That makes it pretty easy to get the right answer without knowing your vocabulary as long as you’ve skimmed through the list before you do the exercise.
I would still recommend this book simply because it’s amusing and the songs will help some people increase their vocabulary.