Owner: A Newman

A call is made by one of the two batsmen to tell the other whether to run or not and is usually some variation on 'yes', 'no', or 'wait'. The convention is that, if the ball is struck in front of the wicket at the striker's end it is the striker who makes the call. If it is struck behind the wicket, then the non-striker should make the call, since he is best placed to see where the ball has gone.
That is the theory behind calls. The practice is sometimes very different. Batsmen will often forget whose call it is supposed to be, with one running and the other rooted to the spot - and woe betide the tailender who runs out the team's star striker!
Some batsmen are notoriously unreliable in their calling, often leading to confusion and catastrophic run outs. The famous England player Dennis Compton was a prime offender, apparently. It was said of him that 'a call by Compton was merely an invitation to open negotiations on the subject!'