Representations of dynamical systems on Banach spaces not containing $l_1$

For a topological group G, we show that a compact metric G-space is tame if and only if it can be linearly represented on a separable Banach space which does not contain an isomorphic copy of $l_1$ (we call such Banach spaces, Rosenthal spaces). Withthis goal in mind we study tame dynamical systems and their representations on Banach spaces.