Cricket used to be a one-dimensional sport. Batsmen batted, bowlers bowled, keepers kept, and captains captained. But now, as Jimmy Ormond is finding out, it's more three-dimensional than ever. Everybody has to chip in: captains must make runs or take wickets, bowlers need to chip in down the order (unless they're Glenn McGrath), and everybody has to contribute in the field. Then there are the wicketkeepers, who are expected to deliver runs like never before. Most of them are up to the task. Kumar Sangakkara's 230 in the Asian Test Championship was the second double-century by a keeper in the past month, after Adam Gilchrist walloped 204 not out - the fastest double-century in Test history, to boot - at Johannesburg.

In Test cricket's 1593-match history, there have only have been six double-hundreds by a keeper - and the highest of those was Andy Flower's 232 against India at Nagpur in 2000-01. As well as those three, there have been hundreds this winter from Deep Dasgupta, Rashid Latif and Adam Parore. Gilchrist has scored almost as many runs (366) in three innings, as Don Tallon (394) - the man given the gloves and a berth at No. 6 in Don Bradman's alltime XI - scored in his 21-Test career. Where on earth would Bradman have batted Gilchrist?

In fact, of the 110 Test hundreds made by keepers, 49 have come since January 1, 1990. And until recently, only three keepers with 10 caps or more had ever averaged 40: Denis Lindsay (40.00) and Les Ames (43.40) would have been top-drawer keeper-batsmen in any era, while Clyde Walcott (40.36) was simply a brilliant batsman who kept from time to time. Now three are three who average over 50 when they have kept, which is usually the preserve of the great: Gilchrist (60.38), Sangakkara (53.80) and Flower (53.71).

Contrast their batting averages with those of some of the greatest keepers in Test history: Wally Grout 15.08, Wasim Bari 15.88, Bob Taylor 16.28, Don Tallon 16.13 and Jackie Hendriks 18.63.

The big difference is that they were all high-quality keepers, and in their day that was enough (although Taylor often lost out to Alan Knott because of Knott's superior batting). And whereas nobody would describe Gilchrist as a great wicketkeeper, he is undoubtedly a great wicketkeeper-batsman, maybe the greatest in the game's history.

Keepers are now picked as much for their prowess in front of the wicket as behind it. Chris Read's mysterious disappearance owes as much to the fact that, spunky cameos aside, he is a No. 8 at best, than to any nervousness with the gloves. Dasgupta for one is a notoriously poor keeper, Ridley Jacobs was christened "Iron Gloves" early in his career, and nobody of the current crop can match the standards set Ian Healy, Jeff Dujon or Jack Russell in the 1980s and 1990s.

The need for keepers who produce with the bat is even greater in one-day internationals, as England showed in New Zealand by replacing James Foster with Marcus Trescothick. Trescothick is not the only one: in the last 10 years John Crawley, Jimmy Adams, David Boon, Alistair Campbell, Justin Langer and Rahul Dravid have all donned the gloves from the start of a one-day match. On the flip side, Sangakkara, Moin Khan, Adam Parore and Junior Murray have all played in Tests as specialist batsmen.

Having a wicketkeeper who can produce with the bat has obvious advantages, as it basically allows a coach to fit 12 into 11. Why have six batsmen when you can have seven? The need is also born of the dearth of genuine allrounders in world cricket. There is really only Shaun Pollock, Jacques Kallis and Chris Cairns. And of those, only Cairns is a genuine bat-six, open-the-bowling allrounder. It's ironic, therefore, that two-thirds of his Test innings have been played at Nos 7 and 8.

In the 1980s there was Imran Khan, Ian Botham, Kapil Dev and Richard Hadlee, but the allrounder as we know it is dead. If the '80s were memorable for that foursome, this decade may well be notable for the exploits of Gilchrist, Sangakkara, Boucher and Flower.

Rob Smyth is on the staff of Wisden.com.

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