The 30th Annual German Conference on Artificial Intelligence (KI-2007) took place in the University of Osnabru ¨ck, September 10–13, 2007. In this volume, you will find papers or abstracts of its six invited talks, 25 full papers, and 21 posters. The full papers were selected from 81 submissions, resulting in an acceptance rate of 32%. AsusualataKIconference,anentiredaywasreservedfortargetedworkshops – ten of them this year – and two tutorials. They are not coveredin this volume, but the conference Web sitewww.ki2007.uos.de will keep providing information and references to their contents. Some topic clusters are apparent in the overall conference program, which reffect recent trends in AI research, convolved with foci of work in Germany and Europe. Examples are learning and data mining, robotics and perception, knowledge representation and reasoning, planning and search – all of them including a healthy number of approaches dealing with uncertainty, contradiction, and incompleteness of knowledge. All in all, KI-2007 provided a cross section of modern AI research and application work. KI-2007 also constituted a “small anniversary,” being the 30th exemplar of its kind. The invited talk by Wolfgang Bibel (accompanied by a paper in this volume) picked up on that occasion by recalling what the field of automated deduction was like 30 and more years ago – in general, and in Germany. He also paid homage to Gerd Veenker, who organizedthe first KI conference (which had a different name at the time) in 1975 and whose field of research was deduction.