Dr. Guy P. Duffield (1909-2000) spent more than 50 years in ministry as a pastor and teacher. He has brought to this work a lifetime of study, research and teaching.Dr. Duffield was directly involved in doctrinal training and developed great proficiency in the ability to explain complex truths in understandable language. In addition to writing numerous articles, booklets and syllabi, Dr. Duffield authored two other books, "Pentecostal Preaching" and "Handbook of Bible Lands." Dr. Nathaniel M. Van Cleave (1907-2002) was a teacher, pastor, mkissionary, theologian, and expository preacher. Gifted by God with unusual ability, Dr. Van Cleave devoted himself to preaching and teaching the Word for more than 50 years. He was fortunate to have his life influenced by the ministry of many significant Pentecostal preachers of the Gospel, and his relationship with them during the first generation of the pentecostal outpouring in North America is part of the important qualification that he brought to the authorship of "Foundations of Pentecostal Theology. "Dr. Van Cleave's book, "Handbook of Preaching, "has been reprinted numberous times and translated for use in many training centers around the world.