The story is long and complicated, so I found it best to dive right in and not come up until you're finished. The children were great characters and developed into a perfect team. I enjoyed the author's creativity devising the initial tests and different ways each of the children conquered them.

The story is based around a huge conspiracy, the implausibility of which really didn't interfere at all with my enjoyment of the book. It's written in a very deliberate, detail-oriented and timeless style, but still letting the kids pretty much be kids, albeit super-smart, well-behaved kids.

Looking forward to reading the sequel!