Book excerpt: The assessment of the ecological integrity of running waters is a prerequisite to an understanding of the effects of human alterations. The evaluation of degradation processes provides key information on how to avoid further negative impacts. The success of future conservation, mitigation and restoration activities will rely on sound assessment methodologies and their ecological relevance and applicability. Assessment methodologies are therefore an integral part of sustainable river management. This book synthesizes and discusses state-of-the-art experiences in assessment methodologies. Including the latest knowledge on structures, processes and functions of running waters as a fundamental basis for developing adequate assessment methods, the book focuses on method development, application, and in particular on integrated assessment methods. This book is directed at scientists and managers with the aim of more effective preservation, restoration and maintenance of the ecological integrity of running water ecosystems.