Here a leading researcher provides a comprehensive treatment of the path following of Unmanned air vehicle(UAV) and coordinated target tracking. Firstly, it describes about the UAV, its definition, its uses, types of UAV and the system architecture of UAV. Different type of path following approaches discussed here. In vector field based trajectory tracking strategies have been discussed. An alternative to this is a nonlinear guidance system (PD controller approximation) as discussed. In Serret-frenet guidance law has been discussed. The Helmsman behavior has been discussed for path following behavior and it is applied for constant line of sight. At a higher level 3D path following approaches discussed. Serret-frenet method for 3D and 3D Vector field method is discussed. Path planning is done by various methods. Tracking of ground vehicle from single UAV is done successfully. Simulation result is shown for all methods. Now finally a coordinated pursuit strategy is discussed ,where Unscented Kalman Filtering is used to estimate the state of a target vehicle that is to be pursued and a set of coordinated target pursuit algorithms are used to address various control issue in mission.