Murray Rosenblatt's interest in random walks on compact semigroups probably came from his work on representations of stationary processes as shifts of functions of independent random variables described in [11], where products of matrices were studied. His papers [12], [5], [13], [14] generalized the work of Levy [2] on random walks on the circle and the work of Kawada and ltd [4] on random walks on compact groups. In [14], he also completely characterized the structure of the limit measures for the special case of compact semigrougs of n x n stochastic matrices.To describe Rosenblatt's work in this area in more detail, we first introduce some definitions and basic facts about compact topological semigroups (see [15] and [3]).1. Every compact topological semigroup S has a minimal two sided ideal K which is called the kernel of S.2. The kernel if is a compact completely simple semigroup which has a Rees structure 1x6x7, where (a) X is a compact left-zero semigroup, Y is a compact right-zero semigroup and G is a compact group.(b) The topology on X x G x Y is the product topology.