We present a new method of constructing a stress-energy-momentum tensor for a classical field theory based on covariance considerations and Noether theory. The stress-energy-momentum tensor T^u _v that we construct is defined using the (multi)momentum map associated to the spacetime diffeomorphism group. The tensor T^u _v is uniquely determined as well as gauge-covariant, and depends only upon the divergence equivalence class of the Lagrangian. It satisfies a generalized version of the classical Belinfante-Rosenfeld formula, and hence incorporates both the canonical stress-energy-momentum tensor and the ``correction terms'' that are necessary to make the latter well behaved. Furthermore, in the presence of a metric on spacetime, our T^u^v coincides with the Hilbert tensor and hence is automatically symmetric.
26 pps. 3/17/92 In: Mathematical Aspects of Classical Field Theory, M.J. Gotay, J.E. Marsden & V.E. Moncrief, Eds., Contemp. Math. 132, 367--392.