  The most recent theoretical and experimental results in the field of
diffractive scattering are reviewed. A parallel between the two current
theoretical approaches to diffraction, the DIS picture in the Breit frame and
the dipole picture in the target frame, is given, accompanied by a description
of the models to which the data are compared. A recent calculation of the
rescattering corrections, which hints at the universality of the diffractive
parton distribution functions, is presented. The concept of generalized parton
distributions is discussed together with the first measurement of the processes
which might give access to them. Particular emphasis is given to the HERA data,
to motivate why hard diffraction in deep inelastic scattering is viewed as an
unrivalled instrument to shed light on the still obscure aspects of hadronic
interactions.
