The 2001 Spring Meeting of the 65th Deutsche Physikalische Gesellschaft was held together with the 65. Physikertagung, in Hamburg, during the pe riod March 26 30 2001. With more than 3500 conference attendees, a record has again been achieved after several years of stabilisation in participation. This proves the continuing and now even increasing, attraction of solid state physics, especially for young colleagues who often discuss for the first time their scientific results in public at this meeting. More than 2600 scientific pa pers were presented orally, as well as posters, among them about 120 invited lectures from Germany and from abroad. This Volume 41 of "Advances in Solid State Physics" contains the written versions of half of the latter. We nevertheless hope that the book truly reflects the current state of the field. Amazingly enough, the majority of the papers as well as the discussions at the meeting, concentrated on the nanostructured solid state. This re flects the currently extremely intensive quest for developing the electronic and magnetic device generations of the future, which stimulates science be sides the challenge of the unknown as has always been the case since the very beginning of Solid State Physics about 100 years ago.