He knew his way around the shelves at Cecil Sharp House even before he started work on December 10, 1979. "I was at library school and I specialised in folk music, so I used this library while I was a student," he said. "When I left college I was unemployed for six months, and the job just happened to come up.
"I was fortunate in a way that I had the credentials for doing it. And I've never been able to escape."
Some of his regulars at the headquarters of the English Folk Dance and Song Society became source material for one of his own projects: the Collecting Folk series he compiled and presented for BBC Radio 2. The eight half-hour programmes told the stories of modern-day field collectors.
He and assistant librarian Elaine Bradke - who's written academic papers on traditional dance - are now putting much of their energy into producing Root and Branch, the new multi-media periodical that examines aspects of Britain's folk heritage. The first edition appeared in 1999; the second will look in detail at the various strands of the Fifties folk revival, drawing on the library's documents, recordings and film material.
"What we're doing in the second one is trying to contextualise the folk movement in the Fifties. People tend to look at folk in a vacuum, without taking into account all the things that were going on around it.
"The idea behind it is to put it in context with things like Windrush [the influx of Afro-Caribbean people into Britain] and the immigration from Ireland, as well as the jazz scene, which was very similar in the way it fragmented into different forms. A lot of the musicians were common to both folk and jazz.
"Protesting was very big in the Fifties, and there were the Radio Ballads on the BBC. It was seen as an austerity decade, but it was a very creative period."
Malcolm sees Root and Branch as a fairly momentous step forward for the library. "It's a real stab at using the resources and the material properly, and trying to put it out to a new generation. And there is one out there that's interested, that's the point. But they never get a chance to access the stuff very well."
Malcolm's also helped compile the Century of Song CD, brought out to mark the 100th anniversary of the foundation of The Folk Song Society in 1998. He also lent his expertise to the vast Voice of the People project, recently brought to fruition by Reg Hall of Bampton Morris fame.
Another highlight of his 20 years' service was an invitation to lecture at the Library of Congress in the United States. "They treated me like royalty."
As it happens, Malcolm hasn't read every one of the hundreds of books in the library. "The skill of a librarian is to scan and note what's good and relevant. It's not just being a repository of literature; it's the guidance you give students and researchers, and the networking - putting people in touch with each other."
Malcolm's 20th anniversary fell just a day after a farewell bash was held at The Spreadeagle pub for Martin Frost, the departing chief executive of EFDSS. Colleagues presented Martin with a leaving present, and then Malcolm found himself on the receiving end of their generosity too.
"It was totally unexpected," he said. "I was a bit embarrassed, to tell you the truth."
Martin Frost's departure
©1999 Simon Pipe, Mark Rogers, The Outside Capering Crew