Network calculus has become a mature and versatile methodology for the analysis of queueing systems with a broad variety of applications ranging from Internet Quality of Service (QoS), wireless networks, to Ethernet with delay guarantees, real-time systems, and feedback control. This is achieved through complementary, problem-specific representations in min-plus or max-plus algebra and the use of worst-case or statistical bounds. The goal of this Dagstuhl Seminar is to gather the deterministic and stochastic Network Calculus community, to discuss recent research activities, to identify future directions, and to strengthen cooperation.