The book "Secret Power; or, The Secret of Success in Christian Life and Work" by Dwight Lyman Moody is a spiritual guide who shares his experience of success in the Christian life. In his book, Moody reveals secret truths and principles that help every believer achieve success in ministry and personal spiritual growth. The author urges his readers to discover the secret of the power of faith and devotion to God in order to achieve true success in the Christian life. This book will be an inexhaustible source of inspiration for all who seek spiritual improvement and wish to reveal their potential in service.