In this book we examined the implications of design space of Time Synchronization in Wireless Sensor Network and found that existing techniques are not adequate to provide appropriately support to some important regions in the design space. We suggested a new approach to fill this gap, by extending the existing time synchronization methods and combined in new ways in order to provide services that can meet the need of applications. We suggested an algorithm to be used by each sensor node to efficiently flood the network to construct a logical hierarchical structure from a designated source point then proposed a Tree Structured Referencing Time Synchronization (TSRT) scheme to minimize the complexity of the synchronization, which works in two phases. The proposed TSRT scheme is further extended for multi-hop Time Synchronization. We described comparison study of proposed scheme with similar existing synchronization protocols. In this we presented a survey and analysis of existing clock synchronization protocols with the suggested features of TSRT for wireless sensor networks.