Donald E. Knuth's five volumes on Computers & Typesetting comprise the definitive user guides and thoroughly documented program code for the Tex and METAFONT systems. This open-source software is widely used around the world by scientists, mathematicians, and others to produce high-quality, aesthetically pleasing text, especially where technical content is included.Tex and METAFONT have now reached a state of maturity that few pieces of software have ever been able to achieve. The start of the Millennium is a perfect time to offer users and libraries the opportunity to fill their reference shelves with an up-to-date and comprehensive collection of Knuth's work, as well as to encourage a broad audience of software developers to learn from the complete, robust, and portable systems built by a master programmer.