The kind of book I enjoyed (and still do) when I was a teen. Shirley is a smart girl, kind of Nancy Drew, who likes to solve mysteries. She has 2 sidekicks, her best friends, who share her adventures. The book is short and nice. The crime is not that hard, and the criminal is quickly caught, which I think fits perfectly for a younger target. If I have the chance, I will not doubt to read the following books in the series.