  In standard quantum field theory, the one-particle states are classified by
the unitary representations of the Poincar\'e group, whereas the causal fields'
classification employs the finite-dimensional (non-unitary) representations of
the (homogeneous) Lorentz group. We investigate the possibility of constructing
fields that transform under the full representation of the Poincar\'e group. We
show that such fields can be consistently constructed, although the Lagrangians
that describe them exhibit explicit dependence on the space-time coordinates.
The inclusion of gravity within the framework of the Poincar\'e gauge theory is
then discussed. A new feature that occurs is that the translational gauge
fields enter the covariant derivative of matter fields. The Poincar\'e-gauge
approach works still well and leads to interesting consequences. The detailed
discussion of the Dirac field is presented and the relation to the earlier
accounts on Poincar\'e-spinors is drawn. Another example that is considered is
the Poincar\'e-vector field. The presentation has a partly didactic character
and is addressed to all the readers who are interested in the rudiments of
quantum field theory and the gauge description of gravity.
