Scofield's correspondence Bible study course was the basis for his Reference Bible, an annotated, and widely circulated, study Bible first published in 1909 by Oxford University Press. Scofield believed that between creation and the final judgment there are seven distinct eras of God's dealing with man and that these eras are a framework around which the message of the Bible could be explained. http://en.wikipedia.org/wiki/C._I._Scofield The Messianic Question No Room in the Inn and Other Interpretation Plain papers on the holy spirit Prophecy Made Plain Rightly Dividing the Word of Truth What Do the Prophets Say? 18 Reasons Why the Church won't Pass Through Where Faith See's Christ The New Life in Christ Jesus Galatians Study