Dettmer's current work involves the appropriation and alteration of media to transform the physical form and/or to selectively remove and reveal content to create new works of fine art. Dettmer explains: "Old books, records, tapes, maps, and other media frequently fall into a realm that too much of today's art occupies. Their intended role has decreased or deceased and they often exist simply as symbols of the ideas they represent rather than true conveyors of content. … When an object's intended function is fleeting, the necessity for a new approach to its form and content arises."
Brian Dettmer's work has been published and exhibited widely in museums, art centers, and galleries around the world, including the Smithsonian (Washington D.C.), Museum of Arts and Design (New York), Virginia Museum of Contemporary Art (Virginia), Museum of Contemporary Art (Georgia), Museum Rijswijh (Netherlands), Wellcome Collection (United Kingdom), the Bellevue Arts Museum (Washington), The Kohler Arts Center (Wisconsin), and the Illinois State Museums (Illinois). His work can be found in public and private collections in the United States, Latin America, Europe, Australia, and Asia.