  We construct the tensor hierarchy of generic, bosonic, 8-dimensional field
theories. We first study the form of the most general 8-dimensional bosonic
theory with Abelian gauge symmetries only and no massive deformations. This
study determines the tensors that occur in the Chern-Simons terms of the
(electric and magnetic) field strengths and the action for the electric fields,
which we determine. Having constructed the most general Abelian theory we study
the most general gaugings of its global symmetries and the possible massive
deformations using the embedding tensor formalism, constructing the complete
tensor hierarchy using the Bianchi identities. We find the explicit form of all
the field strengths of the gauged theory up to the 6-forms. Finally, we find
the equations of motion comparing the Noether identities with the identities
satisfied by the Bianchi identities themselves. We find that some equations of
motion are not simply the Bianchi identities of the dual fields, but
combinations of them.
