An interesting feature in topological insulators (TI) is the topologically protected conducting edge/surface states which can host spin current without dissipation. After a brief introduction to topological insulators, I shall describe our work on a continuum theory of edge states of topological insulators which leads to a "natural" boundary condition for analytical derivation of such edge states. It is well known that the physics behind TIs is basically a single electron mechanism. A natural question that arises is what happens to the edge states in presence of electronic correlation? I shall discuss our work on interaction effects in two dimensional TI ribbons and demonstrate that such ribbons can become Mott Insulating under strong correlation in a synchronous or an asynchronous fashion.