Back in the Eighties, at the height of his powers, he was one of the game's most attractive and popular figures - "the man in the white suit" - reaching two world championship semi-finals and No 4 in the ranking list. In 1983, his 147 in the Benson and Hedges Masters at Wembley was only the third ever scored in competition and, famously, it was the BBC's first. Back in his chair afterwards, he was surrounded by well-wishers: "I look up and I think I'm dreaming because it's Donald Sutherland." He was not. The Canadian actor had been invited along for the evening and this was the first frame of snooker he had ever witnessed. In fact, that trademark white suit was no marketing creation: "I only wore it because my black one was dirty but after that I couldn't wear anything else because people just said: `Where's the white suit?'"
Aggressive in style, engaging in manner, he seemed the white knight charging into battle, putting down the blacks - and, for the 147, the ultimate black - but the image hid an inner turmoil which had been building since his sister suffered burst veins from drug abuse and his mother was killed in a fire caused by arson. For several nights he sat with a shotgun waiting for he knew not who.
Adjustment from the all- encompassing emotional high of competition to the relative monotony of ordinary life was always difficult for him. He also unravelled through the pressure of expectation and the anguish of being nearly but not quite the champion. Jimmy White has suffered similar problems.
In 1985 Stevens admitted that he was "helplessly addicted" to cocaine. "If you've ever had it you want it again," he explained. "There are times when vodka's not enough." From then on he was struggling, albeit with intermittent success, against decline until he could not face the stresses of the circuit any more.
"We don't realise when we're having the time of our lives. I thought it would go on forever," he said of his prime time. But when he eventually acknowledged that it would not, he worked in a lumber yard, as a landscape gardener and as a car salesman. In 1992 he was declared bankrupt. In 1994 he split from his wife with whom he had two sons.
Then at last things started to improve. About a year ago, he began to work his way back into snooker as resident professional at DA's Billiards in Waterloo, Ontario. Comebacks are hard, though. Humiliation lies in wait and conditions are rarely as good as they are at the Crucible. So it was in the atrium of a shopping mall in St John, New Brunswick, last July that Stevens regained the Canadian amateur title he had won in 1978.
Nostalgia was in the air, and so was a large amount of fog since there was no black-out for the mall's enormous skylight. This title took him to Bulawayo in Zimbabwe in November as favourite for the world amateur championship, played in 110 degrees heat. On the one evening the windows were opened, an invasion of flying insects stopped play.
Defeat in the last 32 meant that one return gateway to the world ranking tour was barred but another, the first of the new Americas qualifying events in Hamilton, Ontario, opened. By winning it, Stevens secured one of the 192 places on next season's circuit. If he could win the second in May or beat the winner in a play-off, he would earn exemption to the last 96 of each world-ranking event.
His old friend, Jim Wych, twice a world semi-finalist and now Canada's most active promoter, is among the thousands willing him to succeed: "His popularity has never waned. He hasn't lost his old charisma and charm," he said.
Only time will reveal whether this also applies to his skill and competitive edge. But managing simply to get back on the circuit is a triumph in itself.