Basically this book is about how we are too focused on what's 'womanly' and what's 'manly'. We divide the world into these categories instead of what's most important: our humanness. Humanness distinguishes us from other creatures, who also categorize their species into females and males, and it is possessed by both men and women.
The most detrimental effect of these categorization is that one group, the males, tend to think that their manliness represents humanness.
