  We discuss basic concepts and properties of diffractive phenomena in soft
hadron collisions and in deep-inelastic scattering at low Bjorken-x. The paper
is not a review of the rapidly developing field but presents an attempt to show
in simple terms the close inter-relationship between the dynamics of
high-energy hadronic and deep-inelastic diffraction. Using the saturation model
of Golec-Biernat and Wusthoff as an example, a simple explanation of
geometrical scaling is presented. The relation between the QCD anomalous
multiplicity dimension and the Pomeron intercept is discussed.
