  The present theoretical status of the parameter for direct CP violation
epsilon'/epsilon in the Standard Model is reviewed and compared with most
recent experimental measurements of the same quantity. After collecting the
basic expressions for epsilon'/epsilon, the situation of hadronic matrix
element calculations is summarised. The matrix elements constitute the dominant
source of uncertainty for theoretical determinations of epsilon'/epsilon. For
central values of the input parameters, the numerical analysis then yields
results which are generally below the experimental data. Possible reasons for
these findings are discussed.
