  A construction of massive free fields with arbitrary spin and reversed
spin-statistics relation is presented. The main idea of the construction is to
consider fields that transform according to representations of the Lorentz
group that are doubled in comparison with the representations according to
which normal (physical) fields transform. This allows the definition of
opposite commutation properties for these fields, while the spin of the
particles they describe remains unchanged. The correspondence established by
the construction between fields obeying normal and reversed spin-statistics
relation makes it possible to express e.g. the polarization states,
(anti)commutators, or Feynman propagators of the latter fields in terms of
those of the normal fields to which they correspond. The cases of the scalar
and Dirac fields are discussed in additional detail.
