That's no longer true. The class differences are dramatic. In 2004, 34 per cent of Australian males who left school before year 12 smoked, compared with 11 per cent of university graduates, according to research by the Centre for Behavioural Research in Cancer. And here's the sorry part: those people on the bottom rungs who try to quit are less successful at it than people at the top. It doesn't mean they lack willpower; it probably means they're surrounded by more smokers in their daily lives.

"Smoking is responsible for the most preventable deaths," says Adler. It kills more than 400,000 people in the US every year (and about 15,000 in Australia). And because it has become a low-status behaviour, it is a major factor in explaining the different health outcomes of haves and have-nots.