The inter-war years were dominated by Australia's Don Bradman, statistically the greatest Test batsman of all time. Test cricket continued to expand during the 20th century with the addition of the West Indies (1928), New Zealand (1930) and India (1932) before the Second World War and then Pakistan (1952), Sri Lanka (1982), Zimbabwe (1992), Bangladesh (2000), Ireland and Afghanistan (both 2018) in the post-war period. South Africa was banned from international cricket from 1970 to 1992 as part of the apartheid boycott.
The game on the field is regulated by the two umpires, one of whom stands behind the wicket at the bowler's end, the other in a position called "square leg" which is about 15–20 metres away from the batsman on strike and in line with the popping crease on which he is taking guard. The umpires have several responsibilities including adjudication on whether a ball has been correctly bowled (i.e., not a no-ball or a wide); when a run is scored; whether a batsman is out (the fielding side must first appeal to the umpire, usually with the phrase "How's that?" or "Owzat?"); when intervals start and end; and the suitability of the pitch, field and weather for playing the game. The umpires are authorised to interrupt or even abandon a match due to circumstances likely to endanger the players, such as a damp pitch or deterioration of the light.
Although the main object of the game has always been to score the most runs, the early form of cricket differed from the modern game in certain key technical aspects. The ball was bowled underarm by the bowler and all along the ground towards a batsman armed with a bat that, in shape, resembled a hockey stick; the batsman defended a low, two-stump wicket; and runs were called "notches" because the scorers recorded them by notching tally sticks.
Red parasitic mites sometimes attach themselves to the dorsal region of crickets and may greatly affect them. The horsehair worm Paragordius varius is an internal parasite and can control the behaviour of its cricket host and cause it to enter water, where the parasite continues its lifecycle and the cricket likely drowns. The larvae of the sarcophagid fly Sarcophaga kellyi develop inside the body cavity of field crickets. Female parasitic wasps of Rhopalosoma lay their eggs on crickets, and their developing larvae gradually devour their hosts. Other wasps in the family Scelionidae are egg parasitoids, seeking out batches of eggs laid by crickets in plant tissues in which to insert their eggs.
Crickets (also known as "true crickets"), of the family Gryllidae, are insects related to bush crickets, and, more distantly, to grasshoppers. The Gryllidae have mainly cylindrical bodies, round heads, and long antennae. Behind the head is a smooth, robust pronotum. The abdomen ends in a pair of long cerci; females have a long, cylindrical ovipositor. The hind legs have enlarged femora, providing power for jumping. The front wings are adapted as tough, leathery elytra, and some crickets chirp by rubbing parts of these together. The hind wings are membranous and folded when not in use for flight; many species, however, are flightless. The largest members of the family are the bull crickets, Brachytrupes, which are up to 5 cm (2 in) long.
Before a match begins, the team captains (who are also players) toss a coin to decide which team will bat first and so take the first innings. Innings is the term used for each phase of play in the match. In each innings, one team bats, attempting to score runs, while the other team bowls and fields the ball, attempting to restrict the scoring and dismiss the batsmen. When the first innings ends, the teams change roles; there can be two to four innings depending upon the type of match. A match with four scheduled innings is played over three to five days; a match with two scheduled innings is usually completed in a single day. During an innings, all eleven members of the fielding team take the field, but usually only two members of the batting team are on the field at any given time. The exception to this is if a batsman has any type of illness or injury restricting his or her ability to run, in this case the batsman is allowed "A Runner" who can run between the wickets when the batsman hits a scoring run or runs. The order of batsmen is usually announced just before the match, but it can be varied.
Limited overs cricket is always scheduled for completion in a single day. There are two types: List A which normally allows fifty overs per team; and Twenty20 in which the teams have twenty overs each. Both of the limited overs forms are played internationally as Limited Overs Internationals (LOI) and Twenty20 Internationals (T20I). List A was introduced in England in the 1963 season as a knockout cup contested by the first-class county clubs. In 1969, a national league competition was established. The concept was gradually introduced to the other leading cricket countries and the first limited overs international was played in 1971. In 1975, the first Cricket World Cup took place in England. Twenty20 is a new variant of limited overs itself with the purpose being to complete the match within about three hours, usually in an evening session. The first Twenty20 World Championship was held in 2007. Limited overs matches cannot be drawn, although a tie is possible and an unfinished match is a "no result".