The first edition of the Encyclopædia Britannica is published.

The Encyclopædia Britannica traces its origins to 18th-century Scotland, beginning in Edinburgh in 1768 with the first three-volume edition edited by William Smellie. The project arose during the Scottish Enlightenment, when scholars and printers wanted a more systematic and comprehensive reference work than the alphabetical dictionaries already common in Europe. Rather than merely defining terms, the early Britannica set out to provide longer, thematic essays written by subject experts, which was an innovative format for the time and helped distinguish it from earlier encyclopedic efforts.

Through the 19th century, Britannica expanded in both scope and reputation. Successive editions grew dramatically, and the encyclopaedia increasingly relied on contributions from notable thinkers and specialists. In the 1880s, the publication came under the management of American entrepreneurs who sought broader distribution in the United States. This shift marked the beginning of Britannica’s transformation from a primarily British, scholarly product into an international reference work, with readership and influence stretching across the English-speaking world.

In the 20th century, Britannica became known for recruiting distinguished authors, including Nobel laureates, scientists, and world leaders. The famed 11th edition (published in 1910–1911) is often regarded as a landmark, praised for the quality of its prose and breadth of knowledge. Later editions adopted a more sophisticated editorial structure, including the division into the Micropædia (brief entries), Macropædia (in-depth articles), and Propædia (outlines of knowledge), a design introduced in the 1970s to help readers navigate complex subjects systematically.

The late 20th and early 21st centuries saw Britannica respond to the digital era. It launched CD-ROM and online editions, eventually discontinuing its print version after the 2010s to focus entirely on digital publishing and educational services. Today, the Encyclopædia Britannica operates as an online reference platform, integrating multimedia, regular updates, and educational tools for schools and learners. While the format has changed dramatically from its three-volume beginnings, its goal of organizing and sharing reliable knowledge has remained a defining mission for more than 250 years.