  We introduce in the framework of the linear approximation of General
relativity a natural distinction between General gauge transformations
generated by any vector field and those Special ones for which this vector
field is a gradient. This allows to introduce geometrical objects that are not
invariant under General gauge transformations but they are under Special ones.
We develop then a formalism that strengthens the analogy of the formalisms of
the electromagnetic and the gravitational theories in a Special relativity
framework. We are thus able to define the energy-momentum tensor of the
gravitational field and to fully analyze the gravitational field of isolated
point masses or continuous distributions of them obtained by linear
superpositions.
