  The general seven-dimensional maximal supergravity is presented. Its
universal Lagrangian is described in terms of an embedding tensor which can be
characterized group-theoretically. The theory generically combines vector,
two-form and three-form tensor fields that transform into each other under an
intricate set of nonabelian gauge transformations. The embedding tensor encodes
the proper distribution of the degrees of freedom among these fields. In
addition to the kinetic terms the vector and tensor fields contribute to the
Lagrangian with a unique gauge invariant Chern-Simons term. This new
formulation encompasses all possible gaugings. Examples include the sphere
reductions of M theory and of the type IIA/IIB theories with gauge groups
SO(5), CSO(4,1), and SO(4), respectively.
