Unconstrained canonical action for, and positive energy of, massive spin   2
  Filling a much-needed gap, we exhibit the D=4 Fierz-Pauli (FP) massive s=2 action, and its--manifestly positive--energy, in terms of its 2s+1=5 unconstrained helicity (2,1,0) excitations, after reducing and diagonalizing the troublesome helicity-0 sector. 
S. Deser
gr-qc hep-th