In 1990 came Sid Meier’s Civilization.
About six years later came Civilization II. This was not an expansion or an add-on; it was a re-working of the original game. Many new features were added, new elements of gameplay were introduced, and it was over-all a more complex version of the original.
Two add-on disks were released later for Civ II- Fantastic Worlds was one of them, and I can’t remember the name of the other. These contained new ‘scenarios’- that is, new specifically designed maps and settings to reflect specific challenges or times in history using the basic Civ rules.
Then came Civilization II: Test of Time. This was a small re-working of Civ II, adding in new graphics and turning some of the scenarios from Fantastic Worlds into choices to start from scratch in- so rather than playing a random Earth, one could play a random “Fantasy Earth” with goblins and hawkmen.
Meanwhile, there was a serious dispution in Microprose, publisher of the Civilization seried. Sid Meier had left to found his own company- Firaxis Games- and Microprose ended up going nearly bankrupt and being bought out by Activision.
Question arose as to who actually had possession of the title “Civilization”. Activision claimed that Microprose (and therefore, they) had possession of the title, Sid Meier claimed that he did. While the arguments and lawyers raged, Activision went ahead and published “Civilizaton: Call To Power”, designed in their minds to be Civ 3.
Most reviews of Civilization:CTP were pretty bad- my opinion (and several reviewers agree) is that the designers made a lot of changed solely to make changes, with no real regard for gameplay or balance. I thought CTP was pretty damned lousy compared to Civ II, let alone Alpha Centauri (Sid Meier’s “if you know how Civ ended then you know this is kind of a sequel to Civ but we’re not actually calling it a sequel” game from Firaxis).
I think Sid Meier ended up winning the legal battles, or at least making a deal. “Civilization: Call To Power”'s sequel (which came out about six months ago and apparently fixed some stuff while breaking other stuff, according to the Game Spot review I read) was called “Call To Power 2”, and it’s Firaxis Games that is releasing “Civilization III”.
Now, as for buying Civ 2- you don’t need to. Civ 3 will be a stand-alone product, just as Civ 2 was a standalone from the original Civ. And I don’t know how much enjoyment you’ll get from it- after I played Civ 2, I had no interest in ever playing the original again (so much of what drove me crazy in Civ was fixed in Civ 2), and I expect that after getting and playing Civ 3 I’ll have no interest in going back to Civ 2 (as much of what drives me crazy in Civ 2 seems like it’ll be fixed in Civ 3). If you plan on buying Civ 3 ASAP, then you might not get much use out of Civ 2. OTOH, buying Civ 2 cheap can be a good test to see if you like the concept and the play, and therefore make a future purchase of Civ 3 based more on personal preference rather than surrounding hype.