Differential equations - partial as well as ordinary - are one of the main tools for the modeling of real world application problems. Pursuing the ultimate aim of influencing these systems in a desired way, one is confronted with the task of optimizing discretized models. This volume contains selected papers presented at the International Work shop on "Fast Solution of Discretized Optimization Problems", which took place at the Weierstrass Institute for Applied Analysis and Stochastics in Berlin from May 08 until May 12, 2000. The conference was attended by 59 scientists from 10 countries. The scientific program consisted of 8 invited lectures presented by H. G. Bock (IWR Heidelberg) M. Heinkenschloss (Rice University, Houston) K. Kunisch (University of Graz) U. Langer (University Linz) B. Mohammadi (University of Montpellier) J. Petersson (University of Linkoping) E. Sachs (University of Trier) F. Troltzsch (Technical University of Chemnitz) and 28 contributed talks. The aim of this workshop was to foster the exchange of ideas between the still comparatively separated disciplines of nonlinear optimiza tion on the one side and numerical methods for differential equations on the other side. This is necessary for the successful solution of various current optimization problems in practical applications (shape optimization, topology optimization, pro cess optimization . . . ). Therefore the organizing committee as well as the speakers have come from both these communities.