This book is a discourse on the subject delivered by Swami Ranganathananda, the thirteenth president of the Ramakrishna Order, noted for his humanitarian and progressive views and scientific temper. The nature and the working of the divine grace and many other allied topics, such as self-surrender and self-reliance, are clearly elucidated in this lecture. This lecture, with elaborate quotations from the saints and philosophers of both the East and the West, will help spiritual seekers comprehend the subject from various perspectives and unravel the mystery surrounding the working of the divine grace.