Robert Silverberg 
Face of the Waters 

It is the year 2450. Humanity is scattered among the stars, which teem with intelligent life, while the home world has been destroyed by an inadvertent catastrophe two hundred years before. Thus all Earthmen are exiles, and Earth itself is only a memory.Hydros is a world of great complexity. It has almost no landmass, only a great globe-encompassing ocean with occasional tiny islands. Its seas swarm with apparently intelligent life-forms of a hundred kinds, and one – a bipedal humanoid form – has created a kind of land for itself: floating islands, woven from sea-borne materials, buffered by elaborate barricades against the ceaseless tidal surges that circle the planet.To Hydros have come an assortment of Earthmen. For them it’s a world of no return: having no form of outbound space transportation. This brilliantly inventive novel tells their story, as they travel across the planet’s endless ocean in search of the mysterious area from which no human has ever returned – the Face of the Waters.(First published 1991)