As leaders of the decentralisation movement, Mobile Ad-hoc Networks (MANETs) and Peer-to-Peer (P2P) systems are hot topics in networking community. Decentralisation model puts ordinary network users on the driver's seat, gives them much more control, and stimulates their enthusiasm in active participation. It is believed that decentralisation will replace the client/server model as dominant model in the new century. MANETs and P2P systems share similar theoretical foundations. Both break away from the client/server model using multi-hop multicast. Both are dynamic, highly decentralised, self-organised, and self-healed. However, their levels of real world application are polar apart. Cachelogic reported that in January 2006 P2P traffic accounted for approximately 71% of all Internet traffic. On the other hand, only few MANETs applications have been commercially realized. Remarkable research initiatives in the synergy of P2P systems and MANETs have been sparked by this interesting phenomenon. While most focus on routing, the bootstrapping problem remains indispensable for the transplantation of successful approaches in P2P systems into MANETs. The crucial problem in bootstrapping is topology construction in P2P overlay layer. In this book, a novel solution for this problem, i.e. the Ring Ad-hoc Network (RAN) protocol, is introduced. RAN builds effective rings in node ID space of the overlay layer for ring-based P2P systems like Chord, Pastry, and Virtual Ring Routing. With this ring, lengthy stabilisation is absolutely unnecessary.