I have been wanting to get your books. Which one do you recommend for first time readers of your writings? I will put this one on my wish list at Amazon. Good luck!!
I would read this one first.
Start with this one, sand! Castigo is great. I finished Foreign and Domestic last weekend and am halfway through the Reconquista. If you enjoy Castigo (which I loved), you’ll love Matt’s style overall.
The other three, Enemies Foreign and Domestic, Domestic Enemies -- The Reconquista, and Foreign Enemies and Traitors are all part of the same story line and share a lot of characters. Of that group, you have to read EFAD first. You could read the DETR and FEAT in whatever order you like (both stories stand on their own without having read the other), except that DETR comes first on the timeline and so FEAT would have some slight spoilers in it if you still intended to read DETR.
Castigo Cay isn't part of that plotline and really doens't have any connection to the other books, so it can be read in any order.