New history for the Loire River between Nature and Society Large hydrosystems constitute a major societal challenge, as has been underlined in the various directives that have come out of international conferences on the environment (Stockholm, 1972; the Brundtland report, 1987; Rio, 1992; Kyoto, 2005). The research programme entitled “Zone Atelier Loire” (Loire workshop zone) has emerged from a federation of scientific teams working in human and social sciences, earth sciences and biological sciences. The multidisciplinary research already achieved has provided proof of the substantial impact human societies have had on the geosphere over a span of approximately 5,000 years (i.e., since the Neolithic), with the activities of societies that have been intensifying and accelerating notably during the past two millennia. This research has also demonstrated that land development and activities conducted by societies of the past represent a legacy for modern societies that partially conditions the river's current dynamics. The cumulated effects of all these processes have caused the river bed to settle and modified the flooding hazard, particularly in the middle Loire River zone. The results obtained confirm the usefulness and the contribution of a multi-disciplinary approach in research concerning the environment.