who is Siva..???

If Brahma is the creator, Vishnu the preserver, Siva is the quintessential destroyer. His duty is to destroy all the worlds at the end of creation and dissolve them into nothingness. Modern theories of space do suggest the possible ending of the physical universe after some billions of years through the expansion of a gigantic black hole devouring the matter from endless galaxies. Perhaps Siva would be the black hole performing this task.

However this does not mean that Siva would remain idle till the arrival of that time. Before the worlds really come to an end, Siva has many things to do to keep the worlds going. His first and foremost task is to destroy many things in order to ensure the Rta or the order of the universe. Siva's destruction is not negative. It is a positive, nourishing and constructive destruction that builds and transforms life and energy for the welfare of the world and the beings that inhabit it. He destroys in order to renew and regenerate. His destruction is the destruction of an artist, or a surgeon or a cook. Through destruction he facilitates the smooth transitions of things and events from one stage to another.

He destroys our imperfections in order to ensure our spiritual progress. He destroys our illusions, desires and ignorance. He destroys our evil and negative nature. He destroys our old memories, so that we can move on with the movement of time. He destroys our relationships, attachment, impurities, physical and mental wrong doings, the effects of bad karma, our passions and emotions and many things that stand between us and God as impediments to our progress and inner transformation. And in the end when we have made sufficient progress, when we are ready and prepared, and when we are willing without any inner conflict, he destroys death.

There is no reference to Siva in the Vedas, except as a quality. There are some hymns addressed to Rudra, a fierce storm god, the father of Maruts, who heals with his thousand medicines. (For more information about Rudra please refer the Vedic pantheon). It is said that the practice of worshipping Siva was a non Aryan practice which was slowly incorporated into Vedic religion as an ongoing process of reconciliation with the non Aryan tribes.

by Jayaram V.... http://www.hinduwebsite.com/hinduism/siva.asp