Rudra-Siva in the Vedas,comprising of five chapters, aims at unravelling the mystery surrounding the Vedic deity, Rudra and his worship right from the Samita period down to that of Sutra literature. The concept of Siva, the famous deity of Hindu Trinity, finds it's origin in the Vedic Rudra and no other deity of the Vedic pantheon has undergone so much transformation as noticed in case of Rudra. Ideas associated with this deity sometimes characterise him as falling under outside the Aryan culture. Scholars have viewed him as having a non Aryan origin ascribing aboriginal character to him. But this work attempts to prove the Vedic character of the evolution of Rudra-Siva.