Acquiring data from the deployment area of a WSN is not always easy and multiple issues arise, including the limited resources of sensor devices run with one-time batteries. Additional WSN concerns include the external environment, routing, data aggregation, and ensuring quality of service (QoS) and security. Solutions have been developed for various types of application scenarios, but many problems still remain as open research challenges. This volume covers the various issues associated with WSNs, including their structure, activities, and applications. It reviews current trends in research and development as well as future expectations in the relevant areas.