A wireless body area network (WBAN) is a wireless network of wearable computing devices. The rapid growth in physiological sensors, low power integrated circuits and wireless communication has enabled a new generation of wireless censor networks. A WBAN is a recent trend in medical field where wearable devices which can measure signals such as heart beat and pulse rate are connected in a wireless network. The major challenge it faces is path loss during transmission of the signal. Both LOS and NLOS conditions are considered. This book helps to select the best way to propagate the signal in WBAN. Societal relevance includes monitoring, traffic, crops, infrastructure and health. It allows inexpensive and continuous health monitoring with real-time updates of medical records through the internet. This technology leads to concepts like telemedicine and mHealth which are previously thought impossible.