For an overview of the "user side" read his book "Literary Machines". If you want to understand the technology behind it, consider that there have been two inc

For an overview of the "user side" read his book "Literary Machines". If you want to understand the technology behind it, consider that there have been two incomplete implementations: Udanax Green and Udanax Gold: https://web.archive.org/web/20090226223053/http://www.udanax.com/ https://web.archive.org/web/20090226223053/http://www.udanax... (the domain udanax.com now seems now to be used by someone else). The first was based on a data structure called "Enfilade" (http://www.sunless-sea.net/wiki/EntTheory http://www.sunless-sea.net/wiki/EntTheory), which was invented by Roger Gregory (https://en.wikipedia.org/wiki/Roger_Gregory_(programmer) https://en.wikipedia.org/wiki/Roger_Gregory_(programmer)). Xanadu Gold was based on a data structure called "Ent", which is much more complicated and was according to http://xanadu.com/tech/ http://xanadu.com/tech/ invented by K. Eric Drexler. Understand Enfilades before trying to understand Ents. The best overview of an Ent that I could find (seems incomplete, though) is https://web.archive.org/web/20071027094309/http://www.sunless-sea.net/wiki/Somebody_s%20paper%20on%20the%20Ent https://web.archive.org/web/20071027094309/http://www.sunles...