The bowler's job is to take as many wickets as possible.
That job will be a lot easier if they have control of their line and length, making the batsman's job of scoring runs that much more difficult.
The line is the direction of the ball in accordance to the batsman's stumps, while the length is the area of the pitch where the ball bounces.
The batsman does not need to hit every single ball they face.
So it is the bowler must attempt the batsman into playing a stroke, increasing the chances of taking a wicket.
Cricket commentator Geoff Boycott often uses the phrase "the corridor of uncertainty" as the ideal area to bowl at a batsman.
This is an imaginary channel around and just outside the off-stump where batsmen are unsure whether to play or leave the ball.
Bowling consistently around this area will increase the bowler's chances of taking a wicket.
A bowler's line will also depend on whether the ball is swinging in the air or seaming off the pitch.
Most batsmen like the ball wide outside off stump or on or around leg stump, so avoid bowling in those areas too much.
The length of the ball will determine whether the batsman will play on the front or back foot.
There are five areas the bowler can aim for:
Short of a length
Full length/half volley
Length depends on the type of bowler - fast bowlers will tend to aim for a shorter length to utilise pace and bounce, while spinners need to bowl a good length to deceive the batsman in the air and off the pitch.
The ideal length for a bowler is one where the batsman is unsure whether to play forward or back.
Different pitches will also have an influence on length.
Hard and bouncy pitches favour a shorter length, while slower pitches require a fuller length.