This book is brilliant. I purchased it for my ten-year old, who began it reluctantly. Till seventy-five pages, he was on the verge of quitting. But then, the story peaked-up, and then, it ended when we both watched the movie based on the book!
When I told my prince that the series has four more books, he immediately wanted me to buy all the rest. I, however, bought only the second one, 'The Wind in the Door'. Of course, I will buy the rest later.
The book is not as famous as Potter and Percy Jackson series, but it is good. The language is a tad difficult compared to the two series I have mentioned. But then, this is a sci-fi, even if for children.