Wireless and mobile networks have undergone a tremendous evolution since their start. This was mainly motivated by the need for connectivity everywhere, as exemplified by the philosophy of “always on” access. Mobile telephony was the first need felt by users, followed by the need for mobile Internet applications. Mobile telecommunications networks were the first concretization of mobile telephony, followed by a set of wireless technologies with or without embedded mobility and with or without infrastructure. Obviously, this large deployment of services over mobile and wireless networks is not easy from a network security point of view. This book presents selected up-to-date research on security in wireless and mobile environments, mainly WiFi and self-organized networks such as ad-hoc networks. The selected research work was peer-reviewed and presented at the Mobile and Wireless Networks Security (MWNS) 2008 Workshop in Singapore.