title: Lagrange-Newton Methods for Parameter Identification using Total Variation Regularization abstract: The aim of this paper is to discuss Lagrange-Newton type method for recovering sharp discontinuities for the ill-posed parameter identification problems by using total variation (TV) regularization. By approximating TV, we also discuss some variants of the original Lagrange-Newton algorithm. Numerical experiments indicate that the combination of these techniques enables us to successfully recover discontinuous coefficients under reasonable observation errors.