Hi there. Those who try Civ IV for the first time ought to notice that the installation puts 4 separate EXEs in your PC.

Civ4: IIRC it is the Game of the Year edition. Featuring the famous Baba Yetu song.

Civ4 Warlords: Civ4 GOTY plus enhancements on warfare.

Civ4 Beyond the Sword: GOTY+Warlords plus new enhancements, not on the warring side. For example, there is an early (medioeval) antecessor of the United Nations wonder that helps keeping the peace before the modern age. Features the famous Cupola of the Florence cathedral, by Brunellesci.

Arguably, the player who wants the full experience ought to start Beyond the Sword. Although new players that want to get familiar with the mechanics might want to start the GOTY. Also, players completely focused on war might want to start Warlords. But Beyond the Sword is recommended.

Each expansion provided new scenarios and official mods. Great joy is to be found there. From the Desert War (actually WW2 in northern Africa and the Mediterranean area) of the plain Civ4, to the ambitious space wars of Final Frontier in Beyond the Sword. Even if we do not mention Fall from Heaven or the WW2 Pacific and European scenarios.

Then there is a plethora of mods to download and install. Great stuff there.

So, to finish with the 4 executables, the remaining one is

Civ4: Colonization. A homage to the original Colonization, with the Civ4 engine.

Also, kudos to the interface designers. At 2560x1440 pixels, the game looks awesome and the text is readable.

For Galaxy users: The "play" button starts the plain Civ4. Not Warlords or Beyond the Sword nor Colonization. Civheads will have noticed that already.

Have fun.


Added: In Galaxy, if you push More/Other, you wil the full menu of the four EXEs, as well as the manuals.