Women account for almost half the workforce in western countries, and the lower ranks of many big companies reflect that ratio. But at the top of the corporate ladder it is a different story. For every ten men in the executive suite there is one woman, a ratio that has changed little since the term 'the glass ceiling' was coined two decades ago to de scribe the barrier that allows women to see the top of the corporate ladder, but seems to stop them from reaching it. Despite much discussion, and efforts by both women's and business groups to break that barrier down, the world's biggest companies are still almost exclusively run by men. Yet, at the same time, a growing number of those companies have become convinced that it makes good business sense to have more women in their executive suite. Hardnosed male bastions such as ABB, BP and General Electric have renewed their efforts to help women reach the higher levels, not out of any sense of corporate social responsibility but because they genuinely believe that it is good for their profits. Research from America, Britain and Scandinavia supports their view, showing a strong correlation between share holder returns and the proportion of women in the higher executive echelons. While this does not establish a causal relationship, it does suggest that a corporate culture which fosters women's careers can also foster profitability. Many firms are worried about the coming demographic squeeze that threatens to re duce the supply of qualified men. A few think that women have a unique contribution to make in running modern firms. They are often better at team-building and communications, for example, an advantage in a corporate world that is today increasingly characterized more by informal networks than by ordered cohorts. IBM is convinced that it ran into trouble in the early 1990s partly because its blue suited, like-minded top male executives failed to see the implications of changes in the computer industry. It has sought to diversify its workforce at all levels ever since, and promoting women has been a big part of this effort. Diverse groups are acknowledged to be better at spotting threats coming from unlikely direction. Some of the most enthusiastic promoters of women—Hewlett-Packard and Alcan, as well as IBM—have had considerable success in achieving this in a relatively short period of time. But the vast majority of firms have not. What can they do? It can be inferred from the opening paragraph that