Dexterity is one of the core attributes for characters in Diablo III. It governs the chance that a character will Dodge an attack and increases Demon Hunter's and Monk's damage dealt.
Each point of Dexterity gives:
Before the first attribute changes in 2010, Dexterity was one of the core stats, just as it was in Diablo I and Diablo II.
Dexterity governed a character's chance to critically hit a target, chance to dodge an attack, and chance of being interrupted by getting hit.
1 point of Dexterity gave: (based on Class)
Dexterity was replaced with Precision in 2010's attribute changes.
After the second attribute overhaul in 2012, Dexterity made a comeback, replacing Precision as one of the core attributes.