One who is constantly engaged in the experiments of probing the mysteries of nature is known as muni. Muni means “manansheel tapasvi” i.e., the one who is constantly engaged in understanding the real nature of life and the related problems through tapasya.Muni is an intermediate step between an ordinary man and rishi. The ultimate achievement of tapasya is to become mantra drashta. For rishis being mantra drashta is a must. Tapasya is the easiest and common sadhana but every tapasvi is not muni. Muni studies external circumstances and antahkarana in a state of continuous awareness. As a result of which many secrets in nature are open to him. Munis with such developed vision are called manasvis or manishis.