  I describe the Kaluza-Klein approach to general relativity of 4-dimensional
spacetimes. This approach is based on the (2,2)-fibration of a generic
4-dimensional spacetime, which is viewed as a local product of a
(1+1)-dimensional base manifold and a 2-dimensional fibre space. It is shown
that the metric coefficients can be decomposed into sets of fields, which
transform as a tensor field, gauge fields, and scalar fields with respect to
the infinite dimensional group of the diffeomorphisms of the 2-dimensional
fibre space. I discuss a few applications of this formalism.
