  Correlations in the nuclear wave-function beyond the mean-field or
Hartree-Fock approximation are very important to describe basic properties of
nuclear structure. Attempts are made to explore details of these correlations
in exclusive nucleon knock-out by electron scattering experiments. Basic
results of $(e,e'p)$ experiments are reviewed. The role of correlations in
$(e,e'NN)$ experiments is discussed. Special attention is paid to a consistent
description of the competing effects due to final state interaction, meson
exchange current and isobar currents. Results are discussed for systematic
studies of these features in nuclear matter as well as for specific examples
for the finite nucleus $^{16}$O.
