This Handbook addresses a large number of stakeholders involved in integrated management of transboundary water resources, from national governments to regional organizations, managers and users in the field. They all are invited to work together to face the many current and future challenges. The Handbook offers guidance for the integrated management of transboundary water resources in all of its diversity – for developing and developed countries, intemperate, wet or dry areas. This new work supplements the Handbook for Integrated Water Resources Management in Basins, published in March 2009 during the Fifth World Water Forum in Istanbul.