Hugo is developed by Kent Tessman, whose pages at www.generalcoffee.com/hugo.html provide a good starting point.
The Hugo 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/). The object-oriented source language has a straightforward syntax.
Quoting from the FAQ for the rec.arts.int-fiction newsgroup:
As it is newer than Inform and TADS, fewer people are using it and the Glk-based port to Macintosh doesn't have all the graphics and sounds perks (yet). On the bright side, it is quite powerful and offers advanced sound and graphics capabilities. Mac users are very very grateful for the Glk port, which is quite nice in the non-multimedia areas.
Read the complete Hugo entry at www.plover.net/~textfire/raiffaq/FAQ.htm#Hugo or the entire FAQ at www.plover.net/~textfire/raiffaq/.
The Hugo version of "Cloak of Darkness" was written by John Menichelli (firstname.lastname@example.org), with additional material by Kent Tessman (email@example.com).