This book is to compare the performance of Optimized Link State Routing (OLSR), Ad hoc On-demand Distance Vector (AODV), and Greedy Perimeter Stateless Routing (GPSR) routing protocols performances respective to network's size and density. Each protocol represents MANET routing protocols three categories which are proactive, reactive, and geographical routing protocol, respectively. The evaluation was carried out through simulation and the performance's metrics measurement is in terms of Throughput, average End-to-End (E2E) delay, Packet Delivery Fraction (PDF), and Normalized Routing Load (NRL).