Two umpires take charge of the match on the field of play and communicate their decisions to players and scorers by using a number of signals. For international matches, a third umpire is also on hand to adjudge close decisions such as run outs, stumpings and referrals.
They are also responsible for making sure rules and regulations are upheld and that play starts and finishes at the right time.
Umpires are usually former players who decide they want to remain involved with the game and almost always command huge respect from the players.
Players can be fined if they show dissent at an umpire's decision, for example.