  We generalize the Lagrangian-Hamiltonian formalism of Skinner and Rusk to
higher order field theories on fiber bundles. As a byproduct we solve the long
standing problem of defining, in a coordinate free manner, a Hamiltonian
formalism for higher order Lagrangian field theories. Namely, our formalism
does only depend on the action functional and, therefore, unlike previously
proposed ones, is free from any relevant ambiguity.
