  The central theme of this thesis is noncommutativity in string theory. We
explore in detail how noncommutative structures can emerge in case of the
interacting bosonic string and even in the fermionic sector of superstring
theory. We have shown in various approaches that string coordinates must be
noncommutative in order to be compatible with boundary conditions. These
noncommutative structures lead to new involutive algebra of constraints but
generate same Virasoro algebra, indicating the internal consistency of our
analysis
