Mahendranath Gupta (1854 -1932) was a disciple of the great 19-th century Hindu mystic Rama-krishna, a teacher to Paramahansa Yogananda, a famous 20th-century yogi and an author of The Gospel of Sri Ramakrishna. He met The Gospel of Sri Ramakrishnain his teens and since then he became his devoted disciple. Since the age of 13 Mahendranath wrote a diary, which later became a basis of the book about Sri Ramakrishna, which was his greatest achievement of the great influencer, as it helped spread the teachings of Ramakrishna around the world.