> increase the value of some textbooks quite a bit I think so too! This idea has been around for a long time. Marshall McLuhan suggested the idea of a "custom

> increase the value of some textbooks quite a bit I think so too! This idea has been around for a long time. Marshall McLuhan suggested the idea of a "custom book" almost 50 years ago, yet still nobody has done it: http://minireference.com/book/marshall_mcluhan_quote http://minireference.com/book/marshall_mcluhan_quote I'm currently working on software for generating custom version of my math book. There already exists an XML format called DITA which has conditional-text, but I'm started from scratch.