plasTeX is an open source (python) converter from LaTeX to XHTML. plasTeX's XHTML output is highly compatible with Sigil to assemble an ePub. For example, the XHTML can be split by chapter, section, or even subsection to allow the eReader to load the ePub more efficiently. plasTeX  is highly customizable at four levels of increasing complexity and power. The easiest level (level I) is to create a new theme, for example to create XHTML that can be immediately imported into Sigil for creating and ePub . Level II, also easy, is to add CSS. Level III is to change the page content via Zope Page Templates (ZPTS) . Level IV, the hardest but most powerful, is via customization of the Python code. plasTeX handles most aspects of LaTeX technical books including inline and displayed math, tables, inline and displayed images, footnotes, citations, bibliography, fully automatic LaTeX-style numbering of sections up to depth=6, numbering of tables, figures, and equations, as well as fully automatic LaTeX-style cross referencing among them, to name a few. It supports the most common LaTeX packages such as amsmath and so on. It can be used to convert complex LaTeX source documents to a well structured Website or as an intermediate step to an ePub.