The emergence of network and System Administration, during the latter quarter century, as a discipline of science and engineering, has culminated in a number of paradigms for managing networks of collaborating machines. These include automatic regulation, policy based management, computer immunology, quality control procedures and even the psychology of the user-system interaction. Techniques based on scripting, declarative languages, empirical measurements, and theoretical models, spanning psychology to game theory have been developed. In this volume, key contributions to the discipline are presented through the words of the authors who contributed them. The forum for this thread of ideas has been the USENIX Association's LISA conferences, originally the "Large System Administration" conference. These conferences have played, and continue to play, a unique role in cementing a relationship between researchers and working network and system administrators. Computer scientists,engineers, system administrators and students will each find something of permanent value here. No matter what developments the future brings, these words represent important conceptual foundations of the field. These papers are reprinted here for the first time in a convenient form, along with a commentary reflecting on their significance within the discipline as a whole.