This book is intended to acquaint shell collectors and professional malacologists with various cowry populations inhabiting the waters bordering East Sinai in the Gulf of Aqaba. The presence of 26 cowry species living in this area is confirmed. Populations of 18 species are studied statistically, allowing to form a true notion of their variability The taxonomic identity of these populations is ascertained according to the Biological (Morphological) Species Concept. For these 18 species quantitative and qualitative statistical shell characteristics are provided. Six taxa, in which the shell characteristics are consistently different from these of populations living elsewhere in the Red Sea, are recognized as subspecies endemic to the Gulf of Aqaba. Numerous forms (variety) of cowry shells are presented and analyzed. Abnormalities in cowry shells: rostration, melanism, suffusion, biotic growth and deformations are studied, illustrated and discussed. It is shown that most of them can be explained by the influence of environmental conditions. For four groups of studied populations from East Sinai, their affiliation with related populations of the same species from near-by areas outside the Gulf of Aqaba is traced. New distribution maps are provided for the relevant subspecies. lt is shown how the earlier researchers’ practice of using old synonyms as specific and subspecific cowry names may lead to the taxonomic confusion. Possible ways of solving this problem are discussed and a list of problematic cowry names is provided. A short survey of the unique enviromnental conditions prevailing in the Gulf of Aqaba helps in understanding the origins of the rich mollusc fauna in this area. The book includes a detailed General Index and a bibliography of 187 works.