How I Used Truth by H. Emilie Cady is a foundational work of the New Thought movement, written as a practical spiritual autobiography rather than a theoretical treatise. In this book, Cady shares her personal experiences of applying spiritual “Truth” principles to everyday challenges, especially illness, fear, and lack. The tone is intimate and instructional, inviting readers to see spiritual law as something usable and immediate rather than abstract doctrine. The book emphasizes the idea that Truth is not merely something to believe intellectually, but something to live and actively apply. Cady explains how right thinking, affirmation, and conscious alignment with divine principles can bring about real changes in physical health and life circumstances. Through simple language and illustrative examples, she demonstrates how inner spiritual understanding can dissolve outer problems. Her approach reflects the core New Thought belief in the unity of mind, spirit, and body. Overall, How I Used Truth serves both as testimony and guide. It encourages readers to experiment with spiritual principles in their own lives, stressing personal responsibility and inner transformation. The book remains influential for its clarity, sincerity, and practical focus, making it accessible to readers seeking spiritual growth, healing, and a deeper understanding of applied metaphysical Christianity.