TADS (Text Adventure Development System) is developed by Michael Roberts, whose pages at www.tads.org provide a good starting point.
The TADS authoring system consists of a compiler and an interpreter, both of which are available for many popular platforms (see Jonadab's listings at www.bright.net/~jonadab/if/).
Quoting from the FAQ for the rec.arts.int-fiction newsgroup:
Though slightly fewer games are made using it than Inform, it is still very popular. It is powerful. It has better graphics support than Inform, and HTML TADS is available on the Mac (which is not the case for graphical Hugo). Its library is very object-oriented, which may be a good or bad thing, depending on who you are. It has slightly fewer ports than Inform, especially to ancient computers like the C64 and small computers like the PalmPilot. On the other hand, the reason it can't run on the PalmPilot is that it allows games of any size whatsoever, which is good if your game needs to be huge.
Read the complete TADS entry at www.plover.net/~textfire/raiffaq/FAQ.htm#:TADS (Text Adventure Development System) or the entire FAQ at www.plover.net/~textfire/raiffaq/.
The TADS version of "Cloak of Darkness" was written by Dan Shiovitz (email@example.com), with additional material by Todd Nathan (firstname.lastname@example.org).
NOTE: These pages focus on TADS 2 -- the current version of the system. TADS 3, a complete rewrite with many enhancements, is nearing completion; you can see a TADS 3 implementation of "Cloak of Darkness", by Steve Breslin and others, at the end of the source listing, and both source versions are included on the download menu.