  A total and differential cross-section calculation for the Electroweak
Standard Model reaction $e^+ e^- \rightarrow (Z^0 Z^0) \rightarrow
f_1\bar{f_1}f_2\bar{f_2}(\gamma)$\ including the effects of the finite $Z^0$\
width and, for the first time, all QED initial state radiative corrections
(ISR) is presented. A semi-analytical technique is used: All angular phase
space integrations, five for the tree level process, seven if ISR is included,
are carried out analytically. The remaining phase space variables are the
invariant masses of the two decaying $Z^0$\ bosons for tree level plus the
reduced center of mass energy squared in the ISR case. Invariant masses are
submitted to high precision numerical integration. Semi-analytical and
numerical results for $e^+ e^-$\ center of mass energies between
$\sqrt{s}=130$GeV and $1$TeV are reported. It is shown that the radiatively
corrected cross-section splits into a universal, leading logarithm part with
the tree level cross-section factorizing on one hand and a non-universal
contribution on the other hand. A generalization to the case of Standard Model
neutral boson pair production, $e^+ e^- \rightarrow (Z^0 Z^0, Z^0 \gamma,
\gamma\gamma) \rightarrow f_1\bar{f_1} f_2\bar{f_2}(\gamma)$, is worked out in
detail. The relevance of the presented calculation for the phenomenology of
$e^+ e^-$\ collider physics is discussed, especially for $W$ and Higgs physics
both of which will be important topics in the near future. All significant
technical details of the calculation are explained.
