  We present the basic aspects of deep inelastic phenomena in the framework of
the QCD parton model. After recalling briefly the standard kinematics, we
discuss the physical interpretation of unpolarized and polarized structure
functions in terms of parton distributions together with several important sum
rules. We also make a rapid survey of the experimental situation together with
phenomenological tests, in particular concerning various QCD predictions. In
the summary, we try to identify some significant open questions, to clarify
where we stand and to see what we expect to learn in the future.
