The DDO site gives a brief summary of what monks are about: "Monks use an energy called ki to perform amazing techniques in battle. Usually fighting without weapons and armor, they can assist allies or destroy enemies but take longer to master than the other melee classes." The site continues with an extensive overview of the monk's skills, strengths, and weaknesses, as well as a look at the three paths a monk can choose to follow. The path of shadow offers a more aggressive fighting style, heavier on the damage side than the healing side. The path of light, of course, offers the opposite: more party benefits and less damage over time. And finally, the two-headed heron follows the path of light and benefits its allies, but also delivers damage to enemies as a dual-wielder of monk weapons.
Check out the official site for more information on the monk, and check out our gallery for a more visual look at the class.