The rules of the popular board game provide a basic rule framework. Depending on the map, these are either:
WW2v2
http://www.wizards.com/avalonhill/rules/axis2004.pdf
WW2v2 LHTR
http://www.axisandallies.org/files/AAR_LHTR_v2.0.pdf
WW2v3 / WW2v4
http://www.wizards.com/%5CAvalonHill%5Crules%5CAxAl-AnEd_Rules.pdf
http://www.wizards.com/%5CAvalonHill%5Crules%5CAxAl-AnEd_Errata.pdf
Differences between WW2v2, WW2v2 LHTR, WW2v3 / WW2v4
http://files.meetup.com/232257/AA50%20differences.pdf
Differences between WW2v1, WW2v2, Pacific, D-day
http://www.rogercooper.com/AxisAlliesRulesComparison.htm
http://www.wizards.com/avalonhill/rules/axis2004.pdf
WW2v2 LHTR
http://www.axisandallies.org/files/AAR_LHTR_v2.0.pdf
WW2v3 / WW2v4
http://www.wizards.com/%5CAvalonHill%5Crules%5CAxAl-AnEd_Rules.pdf
http://www.wizards.com/%5CAvalonHill%5Crules%5CAxAl-AnEd_Errata.pdf
Differences between WW2v2, WW2v2 LHTR, WW2v3 / WW2v4
http://files.meetup.com/232257/AA50%20differences.pdf
Differences between WW2v1, WW2v2, Pacific, D-day
http://www.rogercooper.com/AxisAlliesRulesComparison.htm
Deviations, extensions and exceptions from these rules are usually stated in the Game Notes of a map (in the menu once a map is started).
The TripleA engine usually checks for the rules automatically during play, allowing for valid sets only, thus enabling to play the game even without the rules read. There can be some very few exceptions to this though.
The TripleA engine usually checks for the rules automatically during play, allowing for valid sets only, thus enabling to play the game even without the rules read. There can be some very few exceptions to this though.