The comprehensive collection of prints by Wenceslaus Hollar (1607–1677) donated by Sidney T. Fisher to the Thomas Fisher Rare Book Library of the University of Toronto ranks alongside the collections in London, Prague and Windsor. Based on the extensive unpublished correspondence between Sidney Fisher and Richard Pennington preserved in Toronto, this article describes the formation of Fisher’s Hollar collection and Pennington’s work towards ‘A Descriptive Catalogue of the Etched Work of Wenceslaus Hollar, 1607–1677’ (Cambridge, 1982). The activities of Pennington as an agent for Fisher and his dealings with Cambridge University Press are also detailed.