One of the most valuable tools a church can provide to its members is a solid understanding of basic Christian theology. Bringing Theology to Life (IVP) by Darren C. Marks is not a full-scale systematic theology. Rather, he introduces seven key theological ideas (the Trinity, Sin, Incarnation, the Holy Spirit, the Bible and Sacraments, Heaven, and the Church), and shows how these doctrines interact with a dynamic Christian life. The book would provide an excellent basis for a small-group or leadership study in a church.
