Dr. Narayan Dutt Shrimali (1933–1998) was a renowned spiritual guru and an expert in the esoteric sciences of ancient India. A prolific author on subjects like mantra, tantra, astrology, palmistry, and hypnotism, he founded the influential Hindi magazine Mantra Tantra Yantra Vigyan and established the Siddhashram Sadhak Pariwar organization. His works, including Mantra Rahasya and Practical Palmistry, aim to make these complex traditions accessible for practice.