Is a woman allowed to divorce a man in islam?

In judaism a woman cannot divorce a man, but she can ask for one. They are archaic laws that are still practices in israel, making them a source of unending social discord. A man may marry another woman without ever granting the woman a divorce creating an "aguna" (a woman chained to her marriage against her will). Nowadays many aguna cases arise as a result of a husband withholding a "get" (divorce papers) in order to extort money or extract a more favorable divorce settlement or to get even with his wife. In response, aguna groups have organized to support these women and try to find a solution to this problem. Various remedies have been proposed, but as yet, no one solution has common acceptance

What is the islamic teaching regarding divorce?