The resources at this site are available in several formats:
OpenOffice.org
As of the JHDP Encyclopedia version 0.3.3, all development is being done with OpenOffice.org's suite of the same name. The suite is open source and similar to Microsoft's MS Office program. OpenOffice.org's format is open (ie well documented and freely usable), text- and XML-based so it makes a worthy successor to LaTeX for the projects at this site. Writer, the wordprocessing program in Openoffice.org, has several features to recommend it, including the ability to easily link and thus quickly jump to different, related entries. It also converts directly to PDF and PS which makes publishing that much easier.
OpenOffice.org Writer document names end in .sxw
Postscript
I recommend the PostScript (.ps) files for printing, especially if you are on a Linux / Unix system. Also, I understand that Mac's come with postscript viewers. Windows users would need to get a special viewer.
PDF (.pdf) files are made for viewing with Adobe's acrobat reader. They are similar to postscript but users of MS Windows are more likely to have a PDF viewer than a postscript viewer.
HTML
HTML files are text files with web page markup. View them with your browser. For printing, PS or PDF files are better. For viewing on your computer, the OpenOffice.org format is better than the HTML version. (I make the HTML pages available mostly for the benefit of people googling for a specific person or event.)
Note on HTML and older versions of the encyclopedia: The software I used to convert the LaTeX sources into HTML has trouble with the order of the entries - on the index and contents pages, the entries are not in alphabetical order. I do not consider this a serious problem because it only affects those two pages and otherwise all the info is there.
LaTeX
Until about summer of 2004, LaTeX files were the basic files from which I made all the others. They are just text files with special markup that the LaTeX programs use to convert to various file types. Currently, all the LaTeX files have been converted to OpenOffice.org format and the LaTeX files / format is no longer used for the JHDP.
BibTeX
BibTeX files are used with LaTeX to keep flexible databases of bibliographic information and insert references where needed. Since the db is a text file, it is very useful, even if you aren't using LaTeX.