Walter R. Martin was an American Evangelical minister, author, and Christian apologist who founded the Christian Research Institute in 1960. This para-church ministry served as a clearing-house for information, specializing in both general Christian apologetics and countercult apologetics. His writings focused on defending the Christian faith and critically examining other religious groups. Martin's approach was grounded in thorough study of the Bible and historical sources, earning him respect within the Evangelical community.
Since the first edition was published in 1965, "The Kingdom of the Cults" has been the authoritative reference work on major cult systems. Updated regularly, it continues to be a crucial tool in countercult ministry and evangelism for teachers and pastors as well as lay Christians.