This is the story of the Great Barrier Reef, from man's ancient awareness of it, to his realisation that it is a major world wonder of great value to mankind. Beautiful, dangerous and diverse, the Reef provides escape and recreation, a vast resource and limitless retreat for the fisherman, tourist, adventurer, industrialist, scientist, artist and sportsman. But — a small increment of pollution or a slight deprivation of sunlight may set in motion a chain of events that could precipitate a decline and decay of the Reef on which little coral polyps have been working for some six hundred thousand years.