Law vs. Chaos
The Law versus Chaos axis in Dungeons & Dragons predates Good versus Evil in the game rules. In esoteric Greyhawk setting lore, too, the precepts of Law and Chaos predate Good and Evil in the world's prehistory. Players often consider Law and Chaos less relevant to their character than Good and Evil. Confusingly, a Lawful alignment does not necessarily mean that a character obeys a region's laws.
The third edition D&D rules define law and chaos as follows:
Law implies honor, trustworthiness, obedience to authority, and reliability. On the downside, lawfulness can include close-mindedness, reactionary adherence to tradition, judgmentalness, and a lack of adaptability. Those who consciously promote lawfulness say that only lawful behavior creates a society in which people can depend on each other and make the right decisions in full confidence that others will act as they should.
Chaos implies freedom, adaptability, and flexibility. On the downside, chaos can include recklessness, resentment toward legitimate authority, arbitrary actions, and irresponsibility. Those who promote chaotic behavior say that only unfettered personal freedom allows people to express themselves fully and lets society benefit from the potential that its individuals have within them.
It is more common for creatures to be neutral with regard Law/Chaos than Good/Evil. Certain extraplanar creatures, such as the numerous and powerful Modrons, are always Lawful. Conversely, Slaadi are Chaotic, representing beings of chaos. Dwarven societies are usually lawful, while Elven societies are most often chaotic.