"Practical Guide to SGML/XML Filters" presents techniques for processing Standardized General Markup Language (SGML) and EXtensible Markup Language (XML) data and documents. The techniques described in this book also apply to HTML. SGML and XML documents are very structured, which allows programs, also called filters, to easily convert the information to other forms such as Ventura or TeX for typesetting, to HTML or Windows Help for online access, or to CD-ROM for distribution. The book presents seven programming languages commonly used for creating SGML and XML filter programs: AWK, BALISE, C, Perl, OmniMark, SGMLC, and S-Engine. Ten case studies, with working code, of common SGML and XML filter programs are included. The programmer or web master who has to convert documents and data between different formats will find this book useful.