I had read the first book in this series to see if we wanted to get the rest of them for the students and was interested enough to read further. Since I was feeling a little under the weather, I just keep on reading til I finished book 10. These were short and quick reads except for #10 which was somewhat longer and a bit more complicated. Dan (11) and Amy (14) travel all over the world looking for the clues and finding out family secrets as they go.

While these are adventure stories a lot of history and geography are incorporated into the books in a fairly entertaining way. One thing that amused me was that I was reading about Napoleon in Egypt here shortly after finishing a book (See above, message 30) about that very subject. A theme to the series that is made explicit in the last book is that it is better for the branches of the Cahill family to cooperate than it is for them to fight.

Recommended for 10-12 years.