This volume contains the majority of the invited talks of the Spring meeting of the Arbeitskreis Festk"rperphysik of the Deutsche Physikalische Gesellschaft, which has been held in Mnster, Germany, in the period March 22 - 26, 1999. More than 3000 participants, among them PhD students and young post-doctoral scientists, witnessed that this annual gathering of the Deutsche Physikalische Gesellschaft has not lost any of its attractivity. The contents of this volume thus flashlights the 1999 status of Condensed Matter Physics in Germany and may serve as a reference volume for this years activities in this very active field.

Solid state applications.- Organic devices.- Nanostructures.- Quantum Hall effect.- Spin systems.- Superconductivity.- Optical properties.- Scanning probe techniques.- Thin films, surfaces and others