Faith to Live By, Understandin Christian Doctrine by Donald MacLeod and published by Christian Focus Publications.
This is a comprehensive examination of Christian doctrine, practically explained - The Inspiration of Scripture, the Trinity, sin, the Incarnation, the Atonement, Justification, Christian Liberty, Baptism, the Church, the Lord's Supper, the Second Coming, the Resurrection, Hell and Heaven. It equips the reader to present their faith intelligently to others.