Based on empirical studies on the Santal tribes of eastern India, the volume delves into Santal classificatory system of sounds, their mode of transmission of vocabulary of sounds, and importance of material sounds, animal and bird sounds and human sounds. It deals with the functions of the different types of sounds that constitute the Santal auditory world that helps them regulate their lives and maintain harmony in society. Dr. Prasad takes up Santal perception of sound phenomena and relates it to the broader context of the knowledge system. He examines musical instruments used by the Santal of Birbhum district, West Bengal, their use of the principle of symmetry in presentation of drum-beats and these presentations evoking feelings of completeness and continuity. He explains that sound serves as an indicator of time, an indicator of change in seasonal cycle, a means of alarm and protection, and an indicator of cosmic phenomenon.