  In this article, applying different types of boundary conditions; Dirichlet,
Neumann, or Mixed, on open strings we realize various new brane bound states in
string theory. Calculating their interactions with other D-branes, we find
their charge densities and their tension. A novel feature of $(p-2,p)$ brane
bound state is its "non-commutative" nature which is manifestly seen both in
the open strings mode expansions and in their scattering off a $D_p$-brane.
Moreover we study three or more object bound states in string theory language.
Finally we give a M-theoretic picture of these bound states.
