Relevance Feedback in Information Retrieval: The book is intended to be an analysis and an evaluation about relevance feedback methods in information retrieval. These methods are discussed since the early seventies and nowadays the need for relevance feedback is as big as any time before because of the enormous growth of the world wide web and the almost ubiquitous access to it. The tricky task remains the same "filtering out knowledge of the vast amount of information." Search engines can help the user to limit the informational overload but they are returning thousands of documents anyway. Beside other approaches relevance feedback is a technique which enables the user to either implicitely or explicitely refine her or his information need in order to gain knowledge. Therefore the book should provide the reader an overview about relevance feedback techniques which can ease the pain of information overload.