The book is about gender and capacity for violence. The author examines the role of respectively male higher capacity for violence and female higher fear of such violence in constituting the nature of masculinity and femininity. The way she approaches it is by creating a new premise - at some point young women acquired an ability for violence considerably higher than the one men possess. Initially the results seem good - there are numerous cases of abuse and of inequality which are not sustainable anymore. Then, though, women start using their newly acquired power to oppress, just as men used to do.
The author's point is that in a society built on respect for power and violence, gender differences constitute an expression of women's place within hierarchies rather than an expression of some inherently different nature.