  In a functional approach to QCD the infrared behaviour of Landau gauge Green
functions is investigated. It can be proven that the ghost Dyson-Schwinger
equation implies the Gribov-Zwanziger horizon condition. Its relation to the
Kugo-Ojima confinement scenario is elucidated. Positivity violation for gluons
is demonstrated, and the analytic structure of the gluon propagator is studied.
Quark confinement is related to an infrared divergence of the quark-gluon
vertex. It is shown that in the latter various components are non-vanishing due
to the dynamical breaking of chiral symmetry. As a result an infrared finite
running coupling in the Yang-Mills sector is derived whereas the running
coupling related to the quark-gluon vertex is infrared divergent.
  In Coulomb gauge QCD already the one-gluon-exchange (over-)confines. This
leads to a vanishing quark propagator, and thus quarks are confined.
Nevertheless colour singlet quantities derived from the quark propagator are
well-defined. Especially the expression for the quark condensate proves that
chiral symmetry is dynamically broken. As expected the properties of mesons can
be directly calculated whereas the mass of coloured diquarks diverges, and thus
diquarks are confined. The latter nevertheless possess a well-defined size.
  In the third part the results obtained so far will be used to formulate a
covariant Faddeev approach to nucleons. The resulting amplitudes describe the
quark core of the nucleon. Besides the mass of this state also the
electromagnetic form factors are calculated. The results for charge radii and
magnetic moments as a function of the quark current mass provide some
indication what the missing pion cloud may contribute to the nucleons'
properties.
