We develop a scattering theory for perturbations of powers of the Laplacian
on asymptotically Euclidean manifolds. The (absolute) scattering matrix is
shown to be a Fourier integral operator associated to the geodesic flow at
time pi on the boundary. Furthermore, it is shown that on R-n the asymptot
ics of certain short-range perturbations of Delta(k) can be recovered from
the scattering matrix at a finite number of energies.