Why is TeX so hard to use? Because it is in essence a programming language and so it is best viewed from this perspective. In this book, the author presents a complete course in TeX which will be suitable for users of TeX who want to advance beyond the basics. The initial chapters introduce the essential workings of TeX, including a detailed discussion of boxes and glue. Later chapters cover a wide range of advanced topics such as: macros, conditionals, tokens, leaders, file I/O, the line- and page-break algorithms, and output routines. Throughout, numerous examples are given and exercises (with answers) provide a means for readers to test their understanding of the material. As a result, no serious user of TeX will want to be without this text.