  In calculations of (semi-) inclusive events within perturbative Quantum
Chromodynamics, large logarithmic corrections arise from certain kinematic
regions of interest which need to be resummed. When resumming soft gluon
effects one encounters quantities built out of eikonal or Wilson lines (path
ordered exponentials). In this thesis we develop a simplified method to
calculate higher orders of the singular coefficients of parton distribution
functions which is based on the exponentiation of cross sections built out of
eikonal lines. As an illustration of the method we determine the previously
uncalculated fermionic contribution to the three-loop coefficient A^(3).
  The knowledge of these coefficients is not only important for the study of
the parton distribution functions themselves, but also for the resummation of
large logarithmic effects due to soft radiation in a variety of cross sections.
  In the second part of this thesis we study the energy flow pattern of this
soft radiation in jet events. We develop the concept of event shape-energy flow
correlations that suppress radiation from unobserved "minijets" outside the
region of interest and are sensitive primarily to radiation from the
highest-energy jets. We give analytical and numerical results at
next-to-leading logarithmic order for shape/flow correlations in e+e- dijet
events. We conclude by illustrating the application of our formalism to events
with hadrons in the initial state, where the shape/flow correlations can be
described via matrices in the space of color exchanges.
