One of the most productive malacologists in Europe in the latter half of the 19th century was the Swede, Carl Agardh Westerlund (1831–1908). Over 40 years he produced 70 papers, totalling some 5000 pages, in which he introduced hundreds of new names for Palaearctic land and freshwater molluscs. The main bulk of Westerlund’s collection, including types of many of the taxa introduced by him, is in the Gothenburg Natural History Museum. Smaller parts of the material can be found in various museums. His scientific library is housed in the Biomedicinska Biblioteket of the Gothenburg University Library, whereas correspondence, autobiographical notes, diaries, and unpublished manuscript drafts are stored in the Norrköpings Stadsarkiv (eight volumes). A catalogue of the 72 genus-group names introduced by Westerlund is given; Anotus Westerlund, 1883, and Eucampylaea Westerlund, 1876, have precedence over respectively Obscurella Clessin, 1889, and Josephinella F. Haas, 1936. Pupa edentula Draparnaud, 1805 is selected as type species for Columella Westerlund, 1878. The almost forgotten name Thaumasia Westerlund, 1903, is a synonym of Laevicaspia B. Dybowski & Grochmalicki, 1917. A bibliography is given of the malacological publications of Westerlund; special attention is given to publication dates. The author of Pupilla pratensis is Westerlund, 1871 (not Clessin, 1871). A rather unknown portrait of Westerlund is presented.