This was my Book Club's selection last month and the best quote of the evening was that this book is "Nancy Drew for grown-ups...or no, maybe for children." The 11-year-old protagonist, Flavia--an expert in chemistry--is entertaining, the plot is engaging on several levels (the stamps mystery/history is fun and unusual) and the breezy writing-style makes the book readable. However, Flavia's superhero-like knowledge and insights are not believable, especially for a child. There are plot holes and factual errors. And, there's a huge amount of the "mystery" that gets TOLD by one character to another 3/4 of the way through the book when the action should be at its peak. Pleasant reading if you don't think about it too much.