In his book Orthodoxy and Heresy: A Biblical Guide to Doctrinal Discernment, Robert M. Bowman, Jr. recommends the following books:

Soothsayers of the Second Advent, by William M. Alnor

Creeds, Councils and Christ, by Gerald Bray

Heresies: The Image of Christ in the Mirror of Heresy and Orthodoxy from the Apostles to the Present, by Harold O.J. Brown

Unholy Devotion: Why Cults Lure Christians, by Harold Bussell

Foundations of Evangelical Theology, by John Jefferson Davis

The Necessity of Systematic Theology, by John Jefferson Davis

Christian Theology, by Millard J. Erickson

The Doctrine of the Knowledge of God: A Theology of Lordship, by John M. Frame

Evangelical Reunion: Denominations and the Body of Christ, by John M. Frame

Come, Let Us Reason: An Introduction to Logical Thinking, by Norman L. Geisler and Ronald M. Brooks

A Crash Course on the New Age Movement: Describing and Evaluating A Growing Social Force, by Elliot Miller

Witch Hunt, by Robert and Gretchen Passantino

Symphonic Theology: The Validity of Multiple Perspectives in Theology, by Vern. S. Poythress