Sundog: Frozen Legacy is by far one of my most favorite games from the 1980s. Originally written for the Apple II in 1984 by Wayne Holder and Bruce Webster and released by FTL games (founded by Wayne Holder in 1982), I didn't play it until version 3.0 was released as a port to the Atari ST in 1985. Sundog was just one of the successes of FTL. Any gamer awake around that time would recognize that other big FTL hit game series, Dungeon Master. Thankfully, I can still play Sundog on my Mac using NoSTalgia 1.42. This emulator hasn't been updated in several years, but it works well. Of course, you'll need the game ROM to play the game as well. note: I have it on good authority you'll find it on Automation Experts 116.
The original intent behind this post was to write up a history of the game and review the gameplay a bit, until I discovered this has already been done by Maury Markowitz, and quite well in my opinion.
update 131226: Maury's Sundog site moved and I have now updated the link to it - so go check it out! Ian Hadfield's Sundog Information Page has loads of information about the various cities, planets, and commodity exchanges in Sundog.