This collection originated at a conference organized by the Institute Vienna Circle and the University of Vienna on the Vienna Circle and Logical Empiricism and was held in Vienna in July 2001. (cf. The Vienna Orcle and Logical Empiricism. Re-evaluation and Future Perspectives. Edited by Frie- drich Stadler. Dordrecht-Boston-London: Kluwer, 2003, Vienna Circle Institute Yearbook 10). All the essays in this volume with one exception are based on talks presented on that occasion and appear here for the first time. The contributions address a broad range of issues in the philosophy of Rudolf...