The Digital Object Identifier (DOI) is an Internet-based global naming and resolution system that provides for the precise identification, retrieval, and trading of digital items in the form of articles, books, images, bibliographies, supporting data, videos, charts, tables, audio, and other electronic files. Development of the DOI system began in 1996 when content creators and technologists jointly recognized that information and entertainment objects could not be commercially distributed on the Internet unless there was a common system of unique identification for those objects. These early stakeholders envisioned an unambiguous, machine-readable identifier that could be used for all electronic communications and transactions involving content throughout its life cycle, including its creation, editing, publication, distribution, and archiving. Such an identifier would be especially critical for commercial transactions, from initial licensing through sales tracking, royalty computation, and financial reporting.