This book ramifies in its discussion into two basic problems in wireless sensor networks; that of localization and routing protocols, trying to give much more importance at finding efficient solutions to those crucial problems making their use even more critical. Thus, basing on the virtual coordinates system, the reader will find this book quite valuable in presenting some Virtual coordinate systems (VCS) which are free from the GPS tool. And in presenting a new and efficient VCS for wireless sensor network that does not rely on multiple anchors. It relies only on local connectivity information and per-neighbor communication to build a logical topology, since the majority of the proposed virtual coordinates systems suffer from the real obstacle which is the use of anchors as reference points to create virtual coordinates. The proposed VCS is tested by a simple greedy routing algorithm which proves its efficiency in helping to guarantee delivery by assigning to each sensor-node a unique identity.