  The Dirac constraint formalism is applied to linearized gravity to determine
the structure of constraints and construct the canonical Hamiltonian. The
diffeomorphism invariance of the Lagrangian is retrieved by a nontrivial
generalization of the method of Henneaux, Teitelboim and Zanelli, which takes
into account the appearance of spatial derivatives of constraints in the
constraint structure. A couple of first order formulations of the theory are
discussed with the hope of opening avenues on an unambiguous canonical
treatment of the Einstein-Hilbert action in its first order form.
