  In this article we illustrate the relation between the existence of Wiener
integrals with respect to a Levy process in a separable Banach space and
radonifying operators. For this purpose, we introduce the class of
theta-radonifying operators, i.e. operators which map a cylindrical measure
theta to a genuine Radon measure. We study this class of operators for various
examples of infinitely divisible cylindrical measures theta and highlight the
differences from the Gaussian case.
