Introduction: The ebb and flow of law and governance for transboundary aquifers and groundwater resources

Over the past decade, since the articles in this compilation first appeared in 2011, much has taken place in the realm of transboundary groundwater resources. Novel research projects have been initiated, new data and information has been collected, and a number of new agreements and arrangements have been forged among states sharing transboundary groundwater resources. While there is much that remains to be done, a great deal has been achieved.