Ms Moon has created a realistic future of autonomous solar systems interacting with other mainly through trade, with intersystem communication controlled by a commercial monopoly which serves as the closest thing to a de facto interstellar government. The 'Vatta's War' series, of which this book is the fourth, considers the vulnerability of such an arrangement to piracy. It's imaginative, well-plotted and engrossing. Ms Moon's writing abilities have improved greatly since her previous Serrano novels, and the characters populating this series are more complex and morally ambiguous, and therefore much more interesting. The author clearly has firmly held opinions regarding what makes people and societies tick, but manages to get these across without compromising the excitement of her story. Good stuff.