Providing guidance to the senior managers of Hydrological Services, on the key issues they might face, as they lead, manage and administer their services. All aspects of management are reviewed: strategic planning, human resources management, financial management, marketing, asset management, process and quality management, relationships with other institutions. This publication is especially important at a time when NHSs worldwide are typically having their mandate expanded from basic hydrology to hydrology in the broader context of sustainable water resources management.