The Debian GNU/Linux operating system is constantly gaining popularity, despite its reputation of the operating system for professionals and hardcore computer hobbyists. When compared to other popular Linux distributions, this description seems appropriate: Debian approaches Linux system administration rather differently than commonly done, providing text-based configuration mechanisms over graphical user interfaces, and appearing minimalistic and slightly outdated, rather than fully-automated and on the cutting edge. Nevertheless, the unattained robustness, scalability and security, which result from Debian's open development cycle as well as the strict quality control by the developers, attract more and more users every day. This book introduces the concepts and techniques of the Debian operating system, explaining their usage and pitfalls, and illustrating the thinking behind each of the approaches. The goal is not to be a reference book, but to give the reader enough insight into the workings of the project and operating system to learn and embrace the sophisticated and elegant, sometimes at first slightly non-intuitive solutions that have evolved as part of the Debian system over the past decade. While targeted at the well-versed UNIX/Linux administrator, the book can also serve as an excellent resource alongside a standard Linux reference to bootstrap one's Linux experience in Debian's bottom-up philosophy.