A friend once handed me a copy of a book entitled The Green Letters, written by Miles J. Stanford. After reading the first few pages, I knew I had something in my hand that was extraordinary. Day by day during my devotional time I read at least one section and found the book to contain one of the most practical approaches to the various areas of my spiritual life that I have ever read. I asked others to read it, and they confirmed my impressions. The various parts of the book were originally prepared as short letters and were sent to a number of interested friends. They were then compiled into the book which was known as The Green Letters, but in order to make this new printing meaningful to a new audience, the title has been changed to Principles of Spiritual Growth. We are thankful for permission from the author to publish this book for the benefit of a larger group of friends. Set forth in this book are basic principles pertaining to the Christian's spiritual exercises.