As a result, he is credited by every historian of Hong Kong and Macau with revolutionising the field. All of them (including this writer) have benefited from his generosity, his wit and his index cards.

Born on March 10, 1918, in Dayton, Ohio, Smith earned a Master in Divinity from Union Theological Seminary in New York and was ordained a minister in the Evangelical and Reformed Church (now the United Church of Christ). In 1960 he became a missionary and was sent to Hong Kong to teach theology at the Theological Institute in Tuen Mun, and then between 1962 and 1983 at Chung Chi Seminary and its successor, the Chinese University of Hong Kong.

In her book, Foreign Devils - Expatriates in Hong Kong, May Holdsworth described how Smith had to teach the history of the Protestant Church in China, about which he says he knew nothing.

'So I went to libraries to get books on the subject, and what I found was that most of the literature dealt with what the missionaries did and not who the Chinese converts were. But I was not content to teach it just from the missionary standpoint,' Smith told Holdsworth.

So he began a huge, decades-long task. He read English-language newspapers published in Canton from 1822, those later issued in Hong Kong, and the death notices in old Chinese newspapers.

Then followed land registry records, rate books, government gazettes and gravestone memorials in Hong Kong and Macau.

'In compiling my records, I did everything by hand,' Smith told Holdsworth. 'For example, I was about a year and a half in the land registry, going there in the morning, staying until the afternoon, reading every land document seriatim. Each document was in a plastic folder and bound up in packets of 50. It's easy to abstract such documents: you get the date, you get the property, you get the value, you get who bought it, who sold it, and who witnessed the transaction.

'Every day something leapt out at you - a name, for instance - and I'd start making connections with other material I'd seen, say in a newspaper or the tax lists. I did the same thing from rates and valuation records, copying out everything by hand. The period I covered was from 1844 to about 1885. I could have gone on.'

Even when his paying church job disappeared in 1970, he kept pursuing his researches with virtually no money.

Author Valery Garrett remembers Smith from Hong Kong's Public Records Office in the 1970s: 'Every single time I went there, whatever day or month, an elderly gentleman would be sitting in one of the cubbyholes, quietly going through a pile of books and materials, copying things down.

'It was Carl of course, compiling his famous index cards.'

His sight deteriorated almost overnight in the late 1980s.

'I was with him the day after his eyesight suddenly failed. I remember his telling Christa (my wife) and myself that he didn't pray to have his sight restored, but only to be able to accept it if it wasn't. I think this remark in a way characterised his whole personality, says Christopher New, a professor and author.

Author Susanna Hoe recalls Smith 'was not a stuffy church person - though his religion meant a lot to him. He was always ready to be teased by atheist friends, giving his lovely smile and laugh and as good as he was given'.

Helping him throughout his work was his dedicated assistant and scholar Dolly Eusala. Smith relied on her increasingly as his eyes and pillar of strength.

Smith's many writings produced two key books: Chinese Christians: Elites, Middlemen, and the Church in Hong Kong, and A Sense of History: Studies in the Social and Urban History of Hong Kong.

'Every so often a work of history appears that radically changes our understanding of people, place and period. Chinese Christians, first published in 1985, is such a work,' wrote historian Christopher Munn in a new introduction to the 2005 reprint by the Hong Kong University Press.

'The picture that emerges is not that of a passive, faceless Chinese community thriving under British tutelage, but one of men and women using the machinery of colonialism to launch professions, gather riches, secure political influence and build dynasties,' Munn wrote.

By so doing, Smith demolished the popular myth that the Chinese 'did not begin to look on Hong Kong as home until well into the twentieth century'.

Historian and friend Paul van Dyke, who worked with Smith on Armenian and Muslim history in the Pearl River Delta, says that Smith believed 'everyone is important, from the top rulers of society down to the lowliest slaves'.

'With Carl's database, we can now reconstruct the histories of both Hong Kong and Macau, from the bottom up, family by family, street by street, and neighbourhood by neighbourhood,' he said.

The index card collection of Hong Kong materials was given to the Hong Kong Library, his complete Macau card collection is being transferred to the Macau Historical Archives, and other materials are available at the US Library of Congress and the Public Records Office in Hong Kong.

Sarah Choy, archivist at the records office, says the Carl Smith collection is the most frequently used part of her holdings.

Smith's world lives on in his great tales of human aspiration, greed, success and failure, all locked down by the most scrupulous research.

'I've always been left-wing in my thinking, and therefore I wondered, what about labour in Hong Kong? What about the mui tsai [bonded maidservants] and their plight?' Smith told Holdsworth 'What about the Chinese who were shot going over to Sha Tin during the 1925 strike?

'All these things interested me. I tried as much as I could to see them in the context of the Chinese. I know one could not actually see it that way, but I tried. I tried to stand in the Chinese's footsteps.'

In 2002, Smith moved to Macau to work at the Instituto Cultural de Macau.

Many have wondered how Hong Kong has failed to honour Smith in any way, aside from his leading role in the Royal Asiatic Society. His honorary doctorate was awarded in 2005 by the Inter-University Institute in Macau.

Aged 90, Smith died in Kiang Wu Hospital holding hands with his long-time assistant Ms Eusala and her husband Eduardo. A cremation and funeral was held on Thursday in Macau, and a memorial service is planned for Hong Kong for May 3.