Surrey schoolboy Dominic Sibley's 242 against Yorkshire at The Oval last week made him the youngest double-centurion in the County Championship - a record previously held by David Sales, for Northamptonshire v Worcestershire at Kidderminster in 1996, when he was about seven months older than Sibley, who turned 18 on September 5. The only younger man to score a double-century in English first-class cricket was WG Grace, who was nine days younger than Sibley when he made 224 for England v Surrey at The Oval in 1866. There have been 11 younger double-centurions in all first-class cricket, seven on them scored in Pakistan where there are sometimes doubts about the accuracy of birth records. Top of the list is Hasan Raza, 15 years 215 days old when he scored 204 not out for Karachi Whites against Bahawalpur in Karachi in 1997-98.
You're right to exclude Don Bradman, who scored his 20th century in his 35th Test. But apart from him, no one reached 20 quicker than Sunil Gavaskar, in 50 matches. Next comes Matthew Hayden, in 55, quite a way clear of Garry Sobers and Sachin Tendulkar (both 69). As I write 39 players have scored 20 or more Test hundreds: the slowest to reach the mark were Mark Waugh (116 Tests) and Steve Waugh (119).
There's a bit of difficulty here in categorising a specialist. Overall, the leader on the no-centuries list is Shane Warne, who played 145 Tests with a highest score of 99. But he clearly wasn't a specialist batsman, and nor were any of the 51 others who have played in 50 or more Tests without reaching three figures. The answer is Chetan Chauhan, the Indian opening batsman who hardly bowled: he played 40 Tests, but although he reached 50 on 16 occasions he never quite made it to 100, finishing with a highest score of 97. Mike Brearley played 39 Tests for England with a highest score of 91, and Dion Ebrahim 29 for Zimbabwe.
This record has stood for more than 75 years now: the only wicketkeeper to make more than 50 stumpings in Tests is Bert Oldfield, the little New South Welshman who spent much of his long international career (which stretched from 1920-21 to 1936-37) keeping to the teasing legspin of Clarrie Grimmett. Oldfield ended up with 52 Test stumpings, 28 of them off Grimmett's bowling. Next come Godfrey Evans, with 46 stumpings, then Syed Kirmani (38) and Adam Gilchrist (37), just ahead of the leading current keeper, MS Dhoni (36). For the full list, click here. The leader in one-day internationals is Kumar Sangakkara, with 85 stumpings, ten ahead of Dhoni and Romesh Kaluwitharana (both 75).
The left-arm spinner Norman Gifford was 44 when he made his debut for England in a one-day tournament in Sharjah early in 1985 - he had been the assistant manager on a couple of overseas tours, and took over as captain for this tournament when some senior players were rested. Next comes Clive Rice, who was 42 when he captained South Africa in their first official one-day internationals, in India in November 1991. If you include the non-Test teams then the oldest debutant in one-day internationals - and the oldest player overall too - is the Barbados-born opener Nolan Clarke, who was 47 when he played for the Netherlands in the 1996 World Cup.
It's an indication of the scarcity of bowling captains that this is much rarer than both captains scoring hundreds… in fact it has only happened once. In Karachi in December 1959, Richie Benaud took 5 for 93 in Pakistan's first innings, then his opposite number, Fazal Mahmood, replied with 5 for 74 when Australia batted. This was the match made famous by the visit of the American president Dwight Eisenhower on the fourth day.
Steven Lynch is the editor of the Wisden Guide to International Cricket 2013. Ask Steven is now on Facebook