The Delaware postcard collection houses examples of many of the different types of postcards produced from the late nineteenth century to the modern era, including real photo postcards, linen postcards, and photochrome or chrome postcards. It also serves as a visual record of the historic and geographic changes in Delaware over this time period.

Gordon A. Pfeiffer is a Delaware book, postcard, book art, and ephemera collector and an original founder of the Delaware Bibliophiles. The Gordon A. Pfeiffer Delaware postcard and ephemera collection comprises over 1500 postcards depicting Delaware cities and towns, landmarks and events, and advertisements of goods and services in the First State between 1860 and 2008. The collection also contains over 250 QSL broadcasting cards used for promotional purposes by state radio stations.