This book provides an up-to-date synthesis on the different data which are known, at the present time, on the mud snail. From about two hundred years, this small freshwater gastropod had acquired a poor celebrity for its role as an intermediate host in the life-cycle of the liver-fluke Fasciola hepatica and its name had often been associated to the outbreaks of fasciolosis which have occurred in most European countries. Several previous reviews on this snail have already dealt with its role in larval development of the parasite and its control. However, numerous questions were still shelved. Can the habitats of this species be recognized in the field? Is the snail also an intermediate host for other parasites? What is the visceral response of the snail towards larval development of the parasite? Can the snail be raised under laboratory conditions? Can it be eliminated from its natural habitats? Information published on each above point by the authors in France during the past 45 years is compared to reports of foreign teams to draw the main traits on snail ecology, parasitism and control.