Inform is developed by Graham Nelson, whose pages at provide a good starting point.

The Inform authoring system consists of a compiler and an interpreter, both of which are available for many popular platforms. The object-oriented source language, reminiscent of C, is compiled into Z-code (as used by Zork and many other Infocom games); this binary code is processed by a Z-machine interpreter at run-time.

Quoting from the FAQ for the newsgroup:

It is the most highly ported authoring system, and is quite popular. It is very powerful; some of the very advanced techniques are difficult to understand, though. Though it has a few more ports than TADS, HTML-TADS' graphics and sound support are both more powerful and more usable (at the current time) than Inform's. Also, the Z-Machine suffers from the fact that extraordinarily large (and I mean really really big) games do not fit in it. However, for a normal-sized, text-only game that doesn't do extraordinarily complicated hacks (most games fit this description), Inform's problems do not hurt at all.

Read the complete Inform entry at or the entire FAQ at

The Inform version of "Cloak of Darkness" was written by Roger Firth (

NOTE: These pages focus on Inform 6 -- the current version of the system. Inform 7, a completely different approach to IF authorship, is nearing completion; you can see an Inform 7 implementation of "Cloak of Darkness", by Emily Short and Graham Nelson, at the end of the source listing, and both source versions are included on the download menu.