a person who decides who will win a wrestling match, and thus has a lot of control over the storylines and the careers of individual wrestlers
the behind-the-scenes writer who decides angles, gimmicks and the outcomes of matches. Many bookers are involved in hiring and firing wrestlers. Also sometimes used to refer to the event promoter.
This is the guy backstage that decides who's going to win or lose, what's going to happen in the match, how long it's going to last, etc. Example: "Kevin Nash is the worst booker of all time."