Thomas Troward laid out the foundation principles and processes of what he called Mental Science, and is now known as New Thought, a hundred years ago. This book is the last book in the Beyond Words/Atria series called the Library of Hidden Knowledge. It was begun in 2012 and completed in spring of 2021--the perfect moment to immerse oneself in the clear wisdom of this amazing man. His ideas, expressed in extremely lengthy sentences and paragraphs, have become the basis of the mental science and New Thought movement. They have transformed lives for over a hundred years through Unity, Divine Science, and Spiritual Living centers and churches, and have inspired the works of motivational teachers ranging from Napoleon Hill, Wallace Wattles, and Earl Nightengale to Rhonda Byrne in The Secret. As with all the Library of Hidden Knowledge books, this one has two parts. The first part is my "translation," or interpretation, of the original writings from their Victorian prose into modern form and language, with summary points and exercises. The second is Troward's original text.