Cool. I first played Zork on a VAX at Bell Labs, right before Infocom was formally formed in 1979.
There's a great student paper (research project?) from MIT that quite nicely recounts the history of Infocom, the making of Zork, and their fall etc.:
http://web.mit.edu/6.933/www/Fall2000/infocom/infocom-paper.pdf
(yeah, PDF sorry)
Abstract from the paper:
The success and failure of Infocom, a company founded by members of MIT's Laboratory
for Computer Science, resulted from a combination of factors. Infocom succeeded not only
because it made Zork, a text-adventure game, available on personal computers, but also
because it developed an effective system for supporting new platforms, maintained an
engineering culture that excelled at writing computer games, and marketed its products to
the right audience. Similarly, Infocom did not fail simply because it decided to shift its
focus to business software by making Cornerstone, a relational database. Infocom failed
for many reasons that were closely tied to how the company managed the transition to
business products. Behind the scenes, the transition created a litany of problems that hurt
both the games and the business divisions of the company. Combined with some bad luck,
these problems--not simply the development of Cornerstone--ultimately led to Infocom's
downfall.