This is probably one of the best textbooks I've ever used for a course, and that's saying something. It's very easy to read, with clear explanations of various aspects of Islam, and includes essays and studies from many different people who have worked with Muslims or are working in or studying Islam from a variety of backgrounds. I found the section on Islamic history particularly interesting and well written (I'd learned it all before during my archaeology degree, but I'd never had it laid out so clearly in a text before).

Admittedly the book was put together by a Christian organization who works with Muslims, so the book does have a Christian slant, but there's plenty of great information inside no matter what your belief background is (I'd just skip the chapter on church planting... in fact, I only skimmed it as that section wasn't interesting or relevant to me).

As a primer for learning about Islam, this textbook starts from the very beginning and takes you all the way through the history, social / political basics, beliefs, and so on. Very well put together. ( )