Historical ‘island encyclopaedias’ (isolarii, islarios, ‘de insulis’) and their predecessors (Nesiotikà, peripli) were predominately written by authors of the Mediterranean region from the 7th century BCE to the 17th century CE. In this article, we first present an overview of these sources geared towards an Island Studies readership and next consider two main questions: First, how was knowledge about islands produced in the past? And second, can these historical sources motivate new questions for future research? The Balearic Islands have been selected to investigate these questions due to their long history of settlements and trade networks, which prompted their inclusion in many encyclopaedias. In addition, local archaeological and historical sources permit a comparison of emic and etic perspectives. Topics of analysis include descriptions of geography, cultural customs and resource use (including oil, wine, animals, salt, and freshwater), each selected with a view to future comparative studies.