My niece and I have read this book cover-to-cover, and she absolutely loves it! When we first got this book she'd bring it to me and then crawl up into my lap to read through with me. She brought it with her in the car when we'd go places, and she'd look through it in the back seat.
Her brother has also sat in my lap while we look at this book, and his "What's that?" questions show that the book can even engage his growing mind (for a short while). This book has made it clear, however, that as far as my nephew is concerned, we have to work on the idea that skeletons are not necessarily "ghostes" (thanks a lot Scooby-Doo).