The Druid was introduced to Fourth Edition with Player's Handbook 2. The newest incarnation of the class has the Primal power source and the Controller role. They are proficient in simple weapons and light armor, use staves and totems as implements, generally use Wisdom for power attack and damage rolls and, like all primal classes, their powers are called evocations.
Unlike most classes, druids know a third at-will attack power, however they must have at least one and at most two at-will attack powers with the "Beast Form" keyword. Each of the two Druid builds presented in the Player's Handbook 2 emphasizes one of the class's two secondary roles. Guardian druids lean towards the Leader role, focus on Constitution and ranged evocations, and take the "Primal Guardian" class feature, which allows them to use their Constitution bonus in place of their Dexterity or Intelligence bonus when determining AC while wearing light armour, as well as giving some druid evocations additional effects, many of which are based on Constitution. Predator druids lean towards the Striker role, focus on Dexterity and melee and short range evocations, and take the "Primal Predator" class feature, which makes them more mobile while wearing light armor, as well as giving some druid evocations additional effects, many of which are based on Dexterity.
All druids also have "Wild Shape", an at-will power which allows them to switch between their natural and beast forms. While in beast form, they cannot use weapons, and cannot use weapon or implement attack powers without the "Beast Form" keyword. Like clerics and wizards, druids gain Ritual Caster as a bonus feat.