For general polytopes, it has turned out that with respect to many questions it su ces to consider only the simple polytopes, i.e., d-dimensional polytopes where every vertex is contained in only d facets. In this paper, we show that the situation is very di erent within the class of 0 1-polytopes, since every simple 0 1-polytope is the cartesian product of some 0 1-simplices which proves a conjecture of Ziegler, and thus, the restriction to simple 0 1-polytopes leaves only a very small class of objects with a rather trivial structure.