I am indeed grateful to Mr. George Newsholme (Editor of Redemption Tidings), who has not only read the manuscript, but has also written the preface and helped in the final form of this booklet. My hearty thanks are also due to Miss E. F. Dodgson, who patiently typed and retyped the manuscript, and to my wife for the designs of the diagrams. May the Lord be able to use it to His own refreshment, Prov. 25:13, and to the blessing of His people.