Georg Gottlob has made fundamental contributions to both artificial intelligence and to database systems. His research has centred on the algorithmic and logical aspects of knowledge representation, database queries, and recently for web data processing. His work has resulted in the invention of several efficient algorithms for constraint satisfaction, web data extraction and database query processing, some of which are now in widespread use. He has developed a common core to the underlying principles of artificial intelligence and databases. In his work on clarifying the intrinsic complexity of problems in these areas, Gottlob has solved open problems in computational logic, non-monotonic reasoning and database theory.