Since times immemorial, man has modified his physical environment; it is a pressing matter, today, that such changes be henceforth made within the framework of a concerted land planning program. This is particularly necessary where estuaries, coasts, and littoral fringe are concerned. The geologist is called upon to play a primordial role in coastal regions management and planning. He or she must be included in the specialists team whose task it is to bring to a close the series of catastrophics which obliterated beaches and dunes, in areas scattered all over the world, while fostering a rational economic and industrial development.