  The construction of a gauge field theory for elementary particles usually
starts by promoting global invariance of the matter action to a local one, this
in turn implying the introduction of gauge fields. We present here a procedure
that runs the other way: starting from the action for gauge fields, matter is
gauge invariantly coupled on the basis of Lorentz invariance and charge
conservation. This natural approach prevents using the concept of particles
separated from gauge fields that mediate interactions.
