The Anthropological Index Online is based on the journal holdings of The Anthropology Library at the The British Museum (Museum of Mankind) which receives periodicals in all branches of anthropology, from academic institutions and publishers around the world. During 2000 and early 2001, a retrospective conversion was undertaken which has added some 100,000 records going back to 1957. These were originally published on paper as volumes 1-22 of the Anthropological Index.
While both AIO and Harvard's Anthropological Index, also available to Harvard users online, contain citations to the first several ranks of journals in the discipline, the different hemispheric focus means each contains citations to minor and local journals not indexed by the other. AIO also lacks subjects for many of its citations; keyword searches can be limited by geographic region and subfield of anthropology.