Originally published in the 1950s and 1960s, these study aids were authored by Dr. William S. Sadler to serve as texts to train teachers and students of the Fifth Epochal Revelation. These new 6" x 9" paperback books, printed on top-quality paper, feature full-color covers and are thematically organized. These volumes will certainly be a great help to students seeking a greater understanding of this profound gift to mankind.