When Rodge Glass agreed to act as a combined secretary, dogsbody, sidekick and life coach to the notoriously distractable polymath Alasdair Gray, the younger writer expected many things.

He knew he was likely to become the principal fixed point in the blurred flurry of Gray’s creative life as it shifted, muttering like the Mad Hatter, between fiction, fine art, murals and political pamphleteering. He knew his task would be to make the round hole of an ordered life more accessible to the square peg who was his employer.

He did not, however, expect to fall in love with him. “I probably haven’t told Alasdair,” says Glass “But he knows it. It’s very obvious. Both of us are very bad at hiding things. It must be obvious to him that I have a great affection for him, possibly too much in places, which I really had to keep in check in the book. It’s the best way to get a worthwhile, meaningful book.

“Alasdair sat for many hours of interviews and in all that time it must have become painfully obvious that I love him. But I wouldn’t want to embarrass him by saying it to him.”

As Glass admits, everyone in Scotland has an Alasdair Gray story. He has become a type of national mascot, the official Scottish pictogram of the eccentric and scatterbrained artistic genius.

The corollary of this ubiquity, however, is that Gray has become merely part of the landscape, the local wild-haired sage. He has become a walking anecdote, a rattle-bag of tics, mannerisms and oddities, known less for his remarkable work than his propensity to bark in loud comic voices in the public houses of Glasgow.

It’s very much the mission of Glass to rescue Gray’s reputation, as effectively as he once rescued the writer’s wayward mounds of correspondence or the vital notebooks that Gray leaves behind him in pubs, so done, said Gray’s psychiatrist, to elicit gestures of love from those who return them.

The book took Glass into Gray’s domestic life, his health scares — a heart attack, a small stroke and an ulcerated leg — to his desk and his bedside. It was a job that even Gray’s second wife, Morag, had attempted previously and abandoned, thwarted by her spouse’s infuriating scattiness in matters organisational.

Glass, though, had several pressing reasons to stick it out. The first, as he confesses willingly in the biography, was a stalker’s obsession with Gray’s writing, particularly his epic Lanark, a nightmarish vision of Glasgow’s future decline. It was a novel that a friend gave the Manchester-born Glass, 30, to help explain his adopted home. When Gray would wander into the pub where Glass worked as barman, the youth couldn’t prevent himself bombarding the baffled novelist with recondite queries about his work, to which Gray would respond by leaving quickly.

Once his stalker’s ardour had cooled and Glass had been engaged as the writer’s right-hand man, there was another reason he remained attached like a barnacle to the good ship Gray: his own ambitions as a novelist.

“I’m a great believer in apprenticeships,” he says. “Very early on Alasdair said to me, ‘you know my methods, now employ them’. So that’s what I set about doing.”

The result is a biography as whimsical and plain-speaking as Gray’s own writing, one that ignores the conventions of objective biography in favour of a shamelessly personal response, firstly to the work, secondly to the bewildering life that has produced it. Glass deals frankly with Gray’s reliance on alcohol and his tendency to “workaholism”.

The horror show of Gray’s poverty is unpacked, and is seen as symbolic of his inability to negotiate with contingent reality. The elaborate sexual fantasies and the struggle with eczema that are cornerstones of his novels have pebble-dashed his life since his boyhood in the east end of Glasgow.

Along with creative endeavour and the women he has known, alcohol has been the abiding love of Gray’s life. The actor Peter Mullan, a former student of Gray’s, recalls seeing the author at a party, being plied with drink by hangers-on in a nightmarish tableau of social desperation and self-loathing.

Glass adjusted rapidly to the parameters of Gray’s singular world, coming to understand the ruinous pattern by which the novelist had worked for nearly half a century: taking on writing and painting work, too much of it, over which he dithered and fretted, causing him to miss his deadline and complete the work with compromising haste, which discouraged him from commencing the next task promptly.

Glass recounts it all in linear narrative interspersed with his own diary entries on attending to Gray, e-mails from the writer and small detailed essays on recent life events.

As secretary, he would sit by a computer as Gray paraded around the room, dictating impromptu passages that would make their ways into such books as Old Men in Love or The Ends of Our Tethers.

On one occasion Gray punctuated his declamations by urinating in a nearby sink. Gray continued dictating and Glass declined to drink from any kettle filled in the same sink ever again.

Alasdair Gray: The Secretary’s Biography by Rodge Glass is published by Bloomsbury, £25

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