I recently finished an excellent and important book:
Lois M. Farag, ed. The Coptic Christian Heritage: History, Faith, and Culture. London: Routledge, 2014. (It is available here and here.)
There are many books on Coptic Christianity but what makes this one interesting and important is that it was written by Coptic Christians about their own faith. Their insider perspective is missing from most works about Coptic Christianity. I, like most outsiders, might write differently about their faith than they do; and they certainly write differently than most outsiders do, and that is the point. That is what makes this book so special and important. It is an insider's account. They emphasize the sorts of things that are important to them, not the things that are important to outsiders. Although I am familiar with the Coptic faith, I learned a great deal from this book. Their account is to be preferred to the accounts of outsiders. If one is interested in Coptic Christianity, this is a good place to start.