My 5-year-old daughter discovered this book (that I had gotten out of the local library for my 9-year-old son) in her brother's room and immediately took it over. We spent an hour and a half reading it, nearly cover-to-cover as soon as she opened it! She can't yet read, but loved looking at the pictures, listening to the clues, and trying to 'solve the mysteries'. My 9-year-old son enjoyed the book, as well, but was too tempted to figure things out for himself at times, sneaking peek at the 'answers' in the back of the book. The additional clues and 'bonus' mysteries in the answers in the back were an extra, surprise bonus!