East African Great Lakes -- The Lake Tanganyika cichlid species assemblage: recent advances in molecular phylogenetics -- Variance in reproductive success and the opportunity for selection in a serially monogamous species: simulations of the mating system of Tropheus (Teleostei: Cichlidae) -- Assortative mating preferences between colour morphs of the endemic Lake Tanganyika cichlid genus Tropheus -- Variation of territory size and defense behavior in breeding pairs of the endemic Lake Tanganyika cichlid fish Variabilichromis moorii -- Abundance, distribution, and territory areas of rock-dwelling Lake Tanganyika cichlid fish species -- Subtle population structure and male-biased dispersal in two Copadichromis species (Teleostei, Cichlidae) from Lake Malawi, East Africa -- Ecological correlates of species differences in the Lake Tanganyika crab radiation -- The Great Lakes in East Africa: biological conservation considerations for species flocks -- Balkan Lakes Ohrid and Prespa -- Ancient Lake Ohrid: biodiversity and evolution -- The neglected side of speciation in ancient lakes: phylogeography of an inconspicuous mollusc taxon in lakes Ohrid and Prespa -- Concurrent evolution of ancient sister lakes and sister species: the freshwater gastropod genus Radix in lakes Ohrid and Prespa -- Testing two contrasting evolutionary patterns in ancient lakes: species flock versus species scatter in valvatid gastropods of Lake Ohrid -- Sulawesi Lake Systems -- The species flocks of lacustrine gastropods: Tylomelania on Sulawesi as models in speciation and adaptive radiation -- Gene flow at the margin of Lake Matano's adaptive sailfin silverside radiation: Telmatherinidae of River Petea in Sulawesi -- Processes regulating the community composition and relative abundance of taxa in the diatom communities of the Malili Lakes, Sulawesi Island, Indonesia -- The plankton community of Lake Matano: factors regulating plankton composition and relative abundance in an ancient, tropical lake of Indonesia. Ancient lakes are exceptional freshwater environments that have continued to exist for hundreds of thousands of years. They have long been recognized as centres of biodiversity and hotspots of evolution. During recent decades, speciation in ancient lakes has emerged as an important and exciting topic in evolutionary biology. The contributions in this volume deal with patterns and processes of biological diversification in three prominent ancient lake systems. Of these, the famous East African Great Lakes already have a strong tradition of evolutionary studies, but the two other systems have so far received much less attention. The exceptional biodiversity of the European sister lakes Ohrid and Prespa of the Balkans has long been known, but has largely been neglected in the international literature until recently. The rich biota and problems of its evolution in the two central lake systems on the Indonesian island of Sulawesi, in turn, have only lately started to draw scientific attention. This volume aims at deepening the awareness of the unusual biological diversity in ancient lakes in general, and of the role of these lakes as natural laboratories for the study of speciation and diversification in particular. It should stimulate further research that will lead to a better understanding of key evolutionary processes in these lakes, and to knowledge that might help in mitigating the deterioration of their diversity in the future.