Kim Cameron has posted a remembrance of Andreas Pfitzmann, a shining light in the field of security and privacy research. Andreas was a professor at the Technische Universität Dresden and I had the privilege of visiting with him during a PETS conference in 2003.
Andreas was a gracious host and avid hiker and, like Cameron, I will always value his contribution of a clear terminology for the often confusing world of anonymity, unlinkability, undetectability, unobservability, pseudonymity, and identity management.