Since prehistoric times, the Baltic Sea has acted as a crucial nexus that has shaped the languages, folklore, religions, literature, technology, and identities of the Germanic, Finnic, Sámi, Baltic, and Slavic peoples. This anthology first provides an in-depth introduction to the networks among those peoples. The contributors analyse conceptions of geography, followed by explorations of intercultural transfers, such as the slave trade and rune carving techniques. Finally, they turn their attention to mythology and ceremonialism.