\doabstract{Towards tagged PDF} {Ross Moore} {This talk will demonstrate recent work done by the author and \Thanh, to enrich pdf\TeX\ with the primitives to allow the production of ``tagged \PDF''. As this is still very much work-in-progress, the talk will concentrate on presenting various aspects of tagging that allow the advantages of tagging to be easily appreciated. These advantages include, but are not limited to: \item\bull substitution of Unicode characters, for glyph combinations from fonts that use encodings other than Unicode, via \acro{CM}ap resources and other techniques; \item\bull alternative text, to be read by screen-readers; \item\bull extraction of text from \PDF{}s in \XML\ format; \item\bull extraction of mathematical content, in \MathML format. Each of these aspects will be illustrated by examples constructed using an enhanced version of pdf\TeX. Also, I'll try to explain the extra complexity of internal \PDF\ structures required for generating properly tagged structure and content. If there is sufficient time, this may be followed by a discussion of the requirements needed to adjust the \LaTeX\ format and packages, to facilitate the automatic production of properly tagged \PDF, to become conformant with the \ISO--32000--2 standard% \Dash also known as \acro{PDF/UA} (Universal Accessibility, \url{http://pdf.editme.com/PDFUA/}). This standard includes \MathML\ tagging of mathematical content; I wish to acknowledge Neil Soiffer (Design Science Inc., \url{http://accessiblemath.dessci.com/}) for motivation and much helpful advice, and testing, concerning this aspect. }