Appendix A: Old LATEX versus LATEX 2ε
1997
This book is aimed at beginners to LATEX, and it describes the current version, , which was first released in June 1994. However, it is possible that readers may wish to know something about the differences between and the earlier version, LATEX2.09. (For example, you may be given a draft document in LATEX2.09 format by an unenlightened coauthor.) The reference [7] and Appendix D of [6] are excellent sources of information in this area. Here, for completeness, we give a very brief overview of some key differences. Documents written for LATEX2.09 start with the \documentstyle command, whose main argument specifies a document style, as in \documentstyle{article} In addition, optional arguments may be supplied in square braces before the main argument. These options correspond to style files, with the extension sty, that control the formatting in some way. There are built-in options such as 12pt (for increasing the font size by 20%) and twocolumn (for producing two columns per page). Also, it is possible to use other customized style files. For example, \documentstyle [12pt, twocolumn, a_style, b_style] {article} tells LATEX 2.09 to make use of the built-in 12pt and twocolumn options, along with the style files a_style.sty and b_style.sty. By contrast, LATEX documents must start with the \documentclass command, as in \documentclass{article} Like LATEX2.09's \documentstyle, the \documentclass command also allows built-in formatting options such as 12pt and twocolumn to be specified in square braces before the main argument. However, LATEX distinguishes between options that can be supplied to \documentclass and packages, which must be loaded with \usepackage. (Packages, like LATEX2.09's style files, take the form of files with the sty extension.)