How to beat a backstabber at work

What should you do if you hear someone on your team is going above your head and criticizing you to your boss? Whatever you do, don’t ignore it, advises Fortune’s Anne Fisher in her July 2 column. Have you ever found out a subordinate or co-worker was badmouthing you to the boss? Or has an employee tried to badmouth someone else on your team? What did you do about it?