  A perturbative approach to quantum field theory involves the computation of
loop integrals, as soon as one goes beyond the leading term in the perturbative
expansion. First I review standard techniques for the computation of loop
integrals. In a second part I discuss more advanced algorithms. For these
algorithms algebraic methods play an important role. A special section is
devoted to multiple polylogarithms.
  I tried to make these notes self-contained and accessible both to physicists
and mathematicians.
