For bowlers in Test cricket, one figure they wish to keep as low as possible during their career is their strike rate, which indicates the number of balls they deliver per wicket.
It serves as a good indicator of how potent a bowler can be, although it does not take into account the runs they concede.
Since 1964, plenty of bowlers have had very low strike rates during their careers, with some of the lowest coming from some surprising players.
Our starting point is 1964, given that it gives us a 50-year span, but also because before 1964 wickets were poor and bowlers could expect much lower strike rates than their modern peers.
With all that in mind, read on for the top 50 bowlers in modern Test cricket, ranked in order of their strike rate.
All stats courtesy of ESPN Cricinfo, correct as of August 17 2014.