“Yantra Vidya ke 121 Prayog” is a spiritual and occult guide authored by Siddh Baba Audarnath Tapaswi that explores the ancient Indian science of yantra and its practical applications for life enhancement and siddhi (fulfillment of desires). It presents 121 yantra‑based experiments and techniques designed to help readers seek success, protection, prosperity, peace, and overall well‑being through disciplined practice. Rooted in traditional tantra and yantra vidya, the book bridges mystical philosophies with actionable sadhana methods in Hindi, making it accessible to seekers and practitioners. Published by Randhir Prakashan, it reflects a blend of esoteric wisdom and ritualistic procedures that are believed to harness subtle energies for personal transformation. Ideal for readers interested in spirituality, yantra sadhana, and traditional Indian metaphysical practices, this work serves as both a reference and a practical workbook for inner growth and goal realization.