How did a supposedly blind man living on one island collect natural-historical knowledge about an archipelago of tens of thousands? This paper discusses the inter-island information networks of Georg Everhard Rumphius (1627-1702) who, living on the island of Ambon from the age of 25 until his death, explored, experimented, and wrote about the natural world of the Indies while working for the United Dutch East India Company. While the titles of Rumphius’ best-known works prominently feature the adjectival form of the island he considered home—Het Amboinsch Kruydboek and D’Amboinsche Rariteitkamer—these works are rich in detail about other islands in the vast archipelago that straddled the maritime worlds of the Indian and Pacific Oceans. This paper discusses how Rumphius became a mediator of mediators by using a combination of his cross-cultural, administrative, and commercial networks stretching across the archipelago. By engaging with itinerant merchants, Muslim elites, royal emissaries, and slaves, Rumphius collected information about the natural and the supernatural world of the Indies and conveyed such information to others through selective storytelling, personal correspondence, and the gifting of plant samples from Ambon to the administrative center of Batavia. By highlighting Rumphius’ inter-island networks, this paper shows how the process of interpreting different kinds of local knowledge underwent its own complicated circuits of transmission within the archipelago before reaching its intended European audiences. Furthermore, this paper stresses the importance of inter-island correspondence for collecting and correcting natural-historical information that would ultimately be compiled in his monumental Het Amboinsch Kruydboek.