These are booklets that Dr. Gambrell has written over his thirty-five years in world missions. They were written for use in the Candidate School but have since been used by other mission agencies, local churches, and Bible Colleges across the country.
- Effective Deputation
- TULIP, The Heresy of John Calvin
- New Testament Missions
- Ideas for Planning a Mission Conference
- Six Infallible Proofs the Bible is True
- The Ever Changing, Never Changing Catholic Church
- The Local Church – The Headquarters for World Missions