This course concerns the theory and practice of building secure, robust, efficient and evolvable distributed systems. Distributed systems are appearing at all granularities, from planetary scale web services such as Akamai, Ebay and Google, to distributed databases for managing multibillion dollar businesses, to massively parallel multiplayer games, to large scale sensor networks. In each case, there is a need for a deep understanding of fundamental principles if we are to achieve the desired system-level properties.