Historians are increasingly working with material that is not only digital but has been digitized. Early digitization projects aimed to encode data for systematic analysis; more recent projects have sought to reproduce unique archival material in a manner that allows for open-ended historical inquiry without the need to travel to archives and manipulate physical objects. Such projects have undeniable benefits for the preservation of documents and access to them. Yet historians must be aware of the scope of digitization, the reasons why material is chosen to be digitized, and limitations on the dissemination of digitized sources. Furthermore, some physical aspects of sources, and of collections of sources, are lost in their digital simulacra. Nonetheless, digitization and the standardization of metadata offer significant possibilities for future archival research and documentation.