The monograph focuses on the European freshwater pearl mussel Margaritifera margaritifera, which is an endangered bivalve species. Most of its populations in the Russian section of the Baltic Sea basin had never been studied, although they were known in the past to the pearl fishers. 'Rediscovery' included search for the previously unknown populations, revealing the facts of population extinctions, analysis of negative impacts, elaboration of conservation measures, and revealing of regularities in distribution. Patterns of land use and river management were analyzed. 

The book can be used as supplemental reading for courses in biological invasions, ecology and conservation, and biodiversity. The work also contains chapters on global processes (deforestation, desertification, river degradation) and can therefore also be used for general courses in environmental sciences.

Igor Popov was born in Leningrad (now St Petersburg), Russia, in 1971. He studied biology at Leningrad State University between 1988 and 1993. Afterwards, he worked at the Institute for the History of Science at the Russian Academy of Sciences (St Petersburg Branch), Institute for Fisheries, Directorate of Protected Areas of St Petersburg, Konrad Lorenz Institute (Austria), University of Paris 7 Denis Diderot (France) (post-doctoral fellowship supported by Fondation La maison des sciences de l'homme), and N. N. Petrov Research Institute of Oncology. He is currently a researcher in the Department for Applied Ecology (Faculty of Biology, St Petersburg State University). Popov's main research objects were salmonid fishes, bats, marine mammals, freshwater bivalves, and crayfish. His fields of interest include ecology, evolution, history of science, paleontology, zoology, and gerontology as well as various aspects of conservation biology. ORCID: 0000-0002-2564-3294; Scopus ID: 55427914900; Researcher ID: I-4096-2013.