Even by his standards, however, formal recognition of Gray's genius as a visual artist has been a long time coming. Although his distinctive illustrations grace the front covers of his books and his murals decorate many flats and hostelries, a lack of acquisitions in national collections or of any major retrospectives recently prompted his friend and biographer Rodge Glass to ask if his artwork was actually any good.
If events later this week are anything to go by, the answer is an emphatic: "Yes." As the polymath, pamphleteer and avid Scottish nationalist and republican approaches his 76th birthday, exhibitions devoted to his art are opening in two of Edinburgh's leading venues: the Talbot Rice Gallery and the Scottish National Gallery of Modern Art. Add to this the publication of the long-awaited A Life in Pictures and the inclusion of Gray's work in the prestigious British Art Show and it is clear that his place in the pantheon of great Scottish artists - as well as novelists - is finally secure.
Perhaps what has militated against Gray's greater endorsement by the establishment is the sense of chaos that surrounds him. A true eccentric, he is known as much for his unkempt appearance, stream of consciousness speech and high alcohol intake as for his work. Charismatic and irascible, he has taken on the status of a folk hero in the drinking dens of the city's West End His other-worldliness is part of his charm, but has caused him not only to neglect his health, but to miss deadlines and misplace some of his own works.
Gray's lack of conventionality is reflected in his work: his typographical experimentation and his post-modern jokes - like slipping a piece of paper reading: "This erratum slip has been inserted by mistake" in 1982, Janine - are what distinguish him, but have also led to him being viewed by some as inaccessible.
That his visual art work has been so neglected has been a matter of frustration for those around him: "Was (this] because his work was at its best when a public statement, a political act, when it adorned the wall of a pub and was surrounded by words he was already famous for producing?" asked Glass in his book A Secretary's Biography. Whatever the reason, Gray felt it keenly. "When a 70-year-old artist writes the first book ever published about his paintings, he proves that important folk who run art markets don't care for them," he said.Gray was lucky to be born in Riddrie, one of Glasgow's better schemes, at a time when the Butler Education Act was making it easier for working class children to go on to further education. His parents, Alexander and Amy, praised his early drawings and took him out to The Citizens Theatre. During the war, he, Amy and sister Mora were evacuated to a farm in Perthshire, where his lifelong battle with asthma and eczema began.
Installed at Glasgow School of Art, he began writing sections of what would eventually become Lanark as short stories. At the same time, his views on socialism, nationalism and nuclear disarmament began to take shape. Very quickly, his life fell into a pattern: often on the breadline, he took jobs teaching or painting theatre scenery to fund his art work. The commissions started to come: in the mid-50s, he produced murals for the Scotland-USSR Society, the Soviet link proving too much for the school of art, which snubbed the unveiling.
In the mid-70s, Gray joined a writing group where he met Scottish authors including James Kelman and Tom Leonard, later to join him as writers in residence at Glasgow University. Those years were productive, but it wasn't until the publication of Lanark in 1981 that Gray gained widespread recognition. Unlikely Stories, Mostly; 1982, Janine; The Fall of Kelvin Walker and Five Scottish Artists followed.
All Gray's books - except 1982, Janine - are semi-autobiographical and deal with the themes of sex and disillusionment. They are also overtly political, with one of the criticisms of his work being that it tends towards the didactic. The masochistic fantasy scenes in 1982, Janine have also led him to be viewed as a misogynist, though a glance at his personal life suggests his attitude towards women is quite complex. His marriage to Inge Sorenson, who was 17 at the time and gave him his only child, Andrew, broke up in 1970, but they kept in contact, and, in 2000, when Sorenson was dying of cancer she came back to Glasgow and spent a few weeks with him and his second wife Morag McAlpine. He has said his "selfishness" led to most of his break-ups: "I gave (my partners] everything I could see they wanted if I had it, but all the time I was planning to write and paint things. This meant I could retire into a world of inner space in which I was perfectly happy without them, and some of them resented that, but there was nothing to be done about it." This sentence - simultaneously self-critical and arrogant - sums up the contradiction at the heart of Gray. Frequently self-deprecating, he nonetheless seems to believe the normal rules do not apply to him.
There is no sign of this self-absorption diminishing. Indeed, Gray met Glass's proposal for a biography with the tongue-in-cheek, yet revealing riposte: "Be my Boswell. Tell the world of my genius." There is no sign of his work pace slowing either.Although he has suffered ill health, Gray is still involved in many projects, including Fleck (a modern Scottish take on Goethe's Faust). His art works are now selling, his ceiling at Oran Mor has been acclaimed and he is about to embark on a mural in Hillhead tube station. For all that Gray is renowned for "loving the sound of deadlines wooshing by", he continues to heed the words of the epigraph he made famous and which is engraved above his name on the Scottish Parliament building. He works, as he has always done, as though he lived "in the early days of a better nation."