1. Walter Martin, The Kingdom of the Cults. A modern classic that gave inspiration for Christians to identify and witness to non-Christian groups.
2. Francis A. Schaeffer, The God Who is There. A prophet and moving book on “speaking Christianity into the modern world.” I have read this at least ten times in 35 years.
3. Francis Schaeffer, A Christian Manifesto. Explains the worldview collision between Christianity and secularism, especially in relation to politics.
3. CS Lewis, The Abolition of Man. A profound treatment of the modern loss of a foundation for morality and what this means to society.