An invited collection of peer-reviewed papers surveying key areas of Roger Needhams distinguished research career at Cambridge University and Microsoft Research. From operating systems to distributed computing, many of the worlds leading researchers provide insight into the latest concepts and theoretical insights--many of which are based upon Needhams pioneering research work. A critical collection of edited-survey research papers spanning the entire range of Roger Needhams distinguished scientific career, from operating systems to distributed computing and security.  Many of the worlds leading researchers survey their topics latest developments and acknowledge the theoretical foundations of Needhams work. Introduction to book written by Rick Rashid, Director of Microsoft Research Worldwide.