  The measurements of the hadronic final state in deep inelastic scattering at
HERA are reviewed and discussed in the context of QCD. Covered are the general
event properties in terms of energy flows, charged particle production, and
charm and strangeness production. Quark fragmentation properties are studied in
the Breit frame. Event shape measurements allow "power corrections" to be
applied and the strong coupling alpha_s to be extracted. Other alpha_s
measurements are based on dijet rates. Jet rates as well as charm production
have been used to determine the gluon density in the proton. Indications have
been found in the hadronic final state for unconventional, non-DGLAP evolution
at small x, which could be explained with BFKL evolution. Signatures for QCD
instanton effects are discussed and first search results are presented.
