  Classical field theories together with the Lagrangian and Eulerian approaches
to continuum mechanics are embraced under a geometric setting of a fiber
bundle. The base manifold can be either the body manifold of continuum
mechanics, space manifold, or space-time. Differentiable sections of the fiber
bundle represent configurations of the system and the configuration space
containing them is given the structure of an infinite dimensional manifold.
Elements of the cotangent bundle of the configuration space are interpreted as
generalized forces and a representation theorem implies that there exist a
stress object representing forces, non-uniquely. The properties of stresses are
studies as well as the role of constitutive relations in the present general
setting.
