My favorite internet channel,All your History did a 5 videos special on Adventure Games and how the entire genre begun.It's a pretty good special if you ask me,to know how the entire genre started with text adventure games and developed into massive multimillion productions in the early and mid 90s.
Here is the first episode,watch it and click on the other 4 from there.
http://www.youtube.com/watch?v=jEQLc...feature=relmfu