New wireless protocols like W-LAN and Bluetooth allow establishing spontaneous networks and peer-to-peer exchange of information. At the same time standards like Semantic Web and Topic Maps gain acceptance that add semantics to information. This paper introduces Shark. Shark is an acronym and stands for “Mobile Shared Knowledge”. Shark organizes knowledge with help of Topic Maps, synchronizes knowledge inside closed user groups but also enables a peer-to-peer exchange of knowledge by means of Bluetooth. This paper gives an overview of the system and its communication protocols.