The manuscript of The Baroque Cycle was written by hand on 100% cotton paper using three different fountain pens: a Waterman Gentleman, a Rotring, and a Jorg Hysek. It was then transcribed, edited, formatted and printed using emacs and TeX. When it was totally finished, the TeX version of of the ms. was converted to Quark XPress format using an emacs LISP program written by the author.
From http://www.nealstephenson.com/content/author_colophon.htm