What is actually Nirvana -- what are some Tripitaka sources?

What do you know about the **Nirvana**? Most of this community people are from all around the world, and may have different teachers, and level of knowledge may vary. A brief explanation, with reference to the Tripitaka, is much appreciated. --- And, can someone please translate this: It's from the _Abhidhamma Margaya_ ("Way of Abidhamma") by Ven. Rerukane Chandawimala Thero.