Donald was one of the few very important people in Traveller that you could contact if you wanted to say something to Marc Miller himself.
Donald was a master at Traveller canon and had collected lots of information and errata at his Traveller website.
Donald was also an author of Traveller RPG books. I got to know him while I helped him with the MgT Zhodani Book. He was really a great guy to work with.
Now he joins the too long list of Absent Friends. 🙁
RIP Donald McKinney 1967-2015.