Malcolm MacDonald, the editor of TEMPO from 1982 until late 2013, has died, after a four-year battle with cancer. His involvement with this publication predates his formal appointment as editor by a further decade, since it was in 1972 that he was appointed assistant to the then editor, David Drew, gradually taking over Drew's editorial duties as the 1970s unfolded, coming in in the afternoons to a cramped office in the Boosey & Hawkes headquarters on Regent Street. It was in 1981 that he commissioned my first-ever piece of paid writing – a review of Jaroslav Vogel's biography of Janáček – and many other fledgling writers owe their first appearance in print to Malcolm's trust in unproven ability.

By 1982 he was already an acknowledged expert in his own areas of interest, having published two of three volumes on the symphonies of Havergal Brian (1972, 1978, 1983), a life-and-works of John Foulds (1975) and the Master Musicians volume on Schoenberg (1976) which the Schoenberg family still endorses as the best introduction to his music. Other books followed in the course of the years: Ronald Stevenson: A Musical Biography (1989), the Master Musicians volume on Brahms (1990) and, most recently, Varèse: Astronomer in Sound (2003). He prepared published catalogues of the works of Shostakovich (1977), Dallapiccola (1978) and Doráti (1983), all brought out by Boosey & Hawkes. He edited the first two volumes (of a projected six) of Havergal Brian on Music (1986 and 2009). Such a list would be a creditable output in its own right, but it accompanied a voluminous output of music journalism, reviews and other writings – and he composed.

Malcolm MacDonald was born in Nairn, on 26 February 1948, and spent his first five years there, moving to Edinburgh with his family to rejoin his father, head of geography at the Royal High School (and a competent jazz pianist). Malcolm's first encounter with classical music was courtesy of the family pianola, and he later credited his ability to ‘see’ the music he was hearing to watching the piano rolls unwind as he pedalled. The gramophone club at school kindled his musical curiosity, but it was the energetic head of English, the poet and critic Hector McIver, who proved the more persuasive, and MacDonald duly took a three-year degree in English at Downing College, Cambridge – although he did follow it with a one-year course in music.

Based in London from 1971, he worked first as tape librarian for Saga Records – but the job was short-lived: he was incautious enough to ask if there was any holiday pay, and Marcel Rodd, the eccentric owner of the label, immediately showed him the door. It proved a blessing in disguise: a temporary job in a record shop brought him into contact with the editor of Records and Recording, who asked him to join his reviewing staff. Shortly afterwards, the composer and BBC producer Robert Simpson, who knew MacDonald through their mutual enthusiasm for the music of Havergal Brian, introduced him to Karl Miller, editor of The Listener (and a fellow old boy of Royal High and Downing College; he, too, had been a McIver protégé). His career as a reviewer and music journalist was now underway. But he signed his first reviews as Calum MacDonald: there was a Malcolm MacDonald already writing for Gramophone. He remained Calum MacDonald even after the demise of his homonym, contributing most of his reviews in recent years to International Record Review and BBC Music. The BBC regularly commissioned programme notes for the Proms and other concerts, too.

With his partner, the artist Libby Valdez, whom he had met in 1976, he moved to Gloucester, to a house in Stanley Downton on the River Frome, coming into London only when the occasion required it; they married in 2011. He had been writing CD booklet notes for some years, of course, but now became what sometimes seemed a one-man booklet-note industry, writing for a wide range of labels on an even wider range of composers, although with Brahms, Brian and Foulds at its core – if you wanted a note on one of them, he was the obvious man to ask. My CD label, Toccata Classics, was one of those regularly commissioning essays from him, because you knew exactly what you would get: an elegant, insightful text delivered on time and requiring only the tiniest of editorial tweaks, with an uncanny knack of catching the essence of a piece of music in words. You knew a MacDonald text before you glimpsed his name at the end of it, and when you read one of his descriptive commentaries you felt you knew the piece of music in question even before you had heard it.

An aggressive cancer was diagnosed before a visit to Australia for a performance of Brian's Gothic Symphony in 2010, and so he adopted an equally aggressive anti-cancer diet, his continuing vigour astonishing his oncologist on every visit. His written output not only seemed undiminished by his illness; it appeared to increase, as if in defiance. And he was working to the end: on Monday, 19 May, he promised me I'd have a booklet essay I was waiting for in a couple of days, but a day later he collapsed and was admitted to Leckhampton Hospice; there, early in the morning of 27 May, he died. He was 66 years old. Musicians and musicologists around the world had got used to picking his brains, and he shared his knowledge generously and freely. His death leaves a gap in our lives, both professional and personal, which no one else can fill; in the past few weeks I've found myself formulating all manner of questions I want to ask him and no longer can.

He had been composing since his schooldays, with an output mainly of piano pieces and songs, described by the few who saw them as lyrical, often sweet, but with a bitter, dissonant bite. One work that achieved limited circulation in a private recording was a piano prelude, A Waste of Seas, evoking the magnificent isolation of the Hebrides. If you asked Malcolm about his own music, he would answer your question directly but then soon change the subject. I did once request a work-list so that I could see exactly what he had composed, but none ever arrived, and I'm not sure he ever put one together. (A suggestion that he collect his best essays for a volume entitled Malcolm MacDonald on Music met with a similar response.) He was working on a large-scale orchestral piece when he died – and just how skilfully he could write for large forces was demonstrated by his orchestration of the last tableau of Roberto Gerhard's ballet Soirées de Barcelone. How far he got with his own piece remains to be seen; it may yet occasion a radical reassessment of the range of his abilities.