  Since the publication of the models describing a small violation of the Pauli
exclusion principle (PEP) there has been an explosion of word-wide interest in
PEP tests and related theories.
  PEP forbids an atom to have more than 2 electrons in the K-shell. If PEP is
slightly violated, a third electron can occasionally join in. This would result
in an anomalous X-ray emission. A high-sensitivity experiment places an upper
limit of the order of 10^{-26} on the PEP violating parameter.
  I will outline the main theoretical and experimental ideas in this new
exciting area.
