This text focuses on the qualitative aspects of deterministic and stochastic differential equations. Areas covered include: ordinary and partial differential systems; optimal control of deterministic and stochastic evolution equations; control theory of partial differential equations (PDE’s); optimization methods in PDE’s with numerous applications to mechanics and physics; inverse problems; stability theory; abstract optimization problems; calculus of variations; numerical treatment of solutions to differential equations and related optimization problems. These research fields are under very active development and the present volume should be of interest to students and researchers working in applied mathematics or in system engineering. This volume contains selected contributions presented during the International Working Conference on Analysis and Optimization of Differential Systems, which was sponsored by the International Federation for Information Processing (IFIP) and held in Constanta, Romania in September 2002. Among the aims of this conference was the creation of new international contacts and collaborations, taking advantage of the new developments in Eastern Europe, particularly in Romania. The conference benefited from the support of the European Union via the EURROMMAT programme.