Bengt Andersson Euphrasén was born in 1755 in Habo as the son of a poor farmer. However, he had access to a school and gymnasium on Visingsö and traveled to both China and the West Indies (especially the Swedish colony of Saint Barthélemy) where he reported extensively on both plant and animal life and the customs of the people. Essays on ten different fish species were printed during his lifetime in the papers of the Royal Academy of Sciences, and a book on Saint Barthélemy and two neighboring islands was published in 1795, the year before his death. Euphrasén's name is now scientifically associated with six species of fish. Sometimes his book on Saint Barthélemy is quoted, but no thorough analysis of the work has been done before. Nor has his unpublished manuscript of an overview of all the fishes of Sweden, an Ichtyologia Svecica, been subject to closer analysis. His working methods reflect the scientific approach of the time. Euphrasén faced major setbacks in both his scientific and private life, which in their own way also reflect the times. The description of his life and work is richly illustrated with photographs from nature, Euphrasén's publications, his herbarium and, above all, his scientific references, which in many cases have beautifully colored illustrations.