The Science of Religion (1920) is Paramahansa Yogananda's first major published work and a landmark attempt to present spirituality as a universal, rational, and experiential science. Written soon after his arrival in the United States, the book explains that all true religions share a single underlying purpose: to lead human beings from suffering and restlessness to lasting happiness through direct inner experience of the Divine. Yogananda examines the human quest for joy, showing that ordinary pleasures are fleeting because they depend on external circumstances.

True fulfillment, he argues, comes only from contact with the soul's innate bliss, which transcends the senses. This experience is not bound to any creed but can be achieved through systematic spiritual practice-what he calls the "science" of religion.

Drawing on the philosophical traditions of India and Western psychology, Yogananda outlines meditation as the essential method for exploring consciousness, calming the mind, and realizing one's unity with Spirit. He also critiques sectarianism and dogma, inviting readers to approach religion as a universal path open to all seekers.