The reality of female professional success in today's world - a challenge to long-held assumptions about female achievement and sexual inequality.
For most of history, being female defined the limits of a woman's achievements. But now, women are successful careerists equal to men. In Norway, women legally must constitute a third of all boards; in America, women have gone from 3% of practising lawyers in 1970 to 40% today, and over half of all law students.
These changes are revolutionary - but not universal: the 'sisterhood' of working women is deeply divided. Making enormous strides in the workplace are young, educated, full-time professionals who have put children on hold. But for a second group of women this is unattainable: instead, they work part-time, earn less, are concentrated in heavily feminised occupations like cleaning and gain income and self-worth from having children young.
As these two groups move ever further apart, shared gender no longer automatically creates interests in common with other women. The XX Factor lifts the curtain on these social, cultural and economic schisms.
Alison Wolf CBE is the Sir Roy Griffiths Professor of Public Sector Management at King's College London, and director of its international centre for university policy research. She writes widely for the national press, and is a presenter for Analysis on BBC Radio 4.
'An exhilarating piece of analysis that explains once and for all why educated women have done so well and why they have become a class apart. Just when you thought you never wanted to read another word on working woman, here comes Alison Wolf', Lucy Kellaway
'Alison Wolf's skill is to use facts where others have only opinions. The results will infuriate and stimulate almost every reader', John Kay
'Powerful, brilliantly argued, provocative and original - an outstanding book from a compelling thinker', Tim Harford, author of THE UNDERCOVER ECONOMIST and ADAPT
'Wolf has written an exhaustive, intelligent, thoughtful and at times provocative and idiosyncratic analysis of what it is to be an elite woman. By laying out the choices that women are faced with and the consequences of their actions, Wolf is ensuring that we do not have to walk blindfold into the future.', The Financial Times
'A crucial bible for anyone wanting to check up on anything about contemporary woman.', Observer
'Full of such factual richness... The XX Factor is a feast of data.', The Sunday Times
'Alison Wolf has made a brilliant, lucid, and original contribution to the debate about women and the modern economy. If you care about women, work and families in the world today, you must read this passionate, fact-filled book.', Chrystia Freeland, author of Plutocrats
'Just when you thought you never wanted to read another word on working woman, here comes Alison Wolf sweeping away the sloppy prejudices and dreary whining, presenting us with some bracing facts. The XX Factor is an exhilarating piece of analysis that explains once and for all why educated women have done so well (though will never be 50:50 in the boardroom) and why they have become a class apart to the other four fifths. Cheering and sobering by turns, it puts to shame almost every other book that has been written on this subject', Lucy Kellaway
'Highly readable and informative', Paul Seabright, Times Literary Supplement
'The book is fascinating and there is plenty of food for thought within it', Henrietta Royle, Management Today
'Engagingly written ... has a light touch and is full of personal anecdotes, but it is also well footnoted, with a scholar's careful attention to sources', Sylvia Walby, Times Higher Education Supplement
'An exhaustive, provocative analysis', Lynda Gratton, London Business School, Financial Times Summer Reading
'With the XX Factor Wolf accomplishes a rare feat: she combines real breadth with real depth. No matter how much you think you know about this hotly debated subject, and whether or not you agree with every one of Wolf's ideas, you will come away from her book with new information - some merely amusing, but some foundation-shaking', New York Times Book Review