This is the first comprehensive study of an east African lake for thirty years. It represents the culmination of research expeditions which stretch back twenty years and is thus able to pick up long term changes which the individual research activities do not reveal. Lake Naivasha is a tropical lake whose natural fluctuations are now dwarfed by human impacts. Papers show how the irrigation for horticulture and power cooling has reduced the lake depth significantly; exotic arrivals have altered the plant community beyond recognition and its commercial value as a fishery and a tourist feature...