A crucial part of the library is provided by the Seven Islands collection which consists of over 7500 volumes in addition to other related documents. This collection is the primary attraction for Greek and foreign researchers who come to the reading room to study the rare and unique materials that it contains. The collection comprises items which in general follow the order laid down by the bibliographer Emile Legrand.
The books date from the seventeenth century and the collection continues to be augmented and enriched up to the present day. During this time books have been acquired which are not confined to the history of the Seven Islands but include information regarding the genealogy, travel and geography of the Ionian Islands generally.