+Murray positions his work as a corrective to a "blank slate" orthodoxy that refuses to entertain any possibility of biological influences on group differences. The three parts of the book are pitched not simply as "stuff we know about biological influences on sex, race, and class difference" (the oblivious science nerd approach I prefer), but as a rebuttal to "Gender Is a Social Construct", "Race Is a Social Construct", and "Class Is a Function of Privilege." At the same time, however, Murray is careful to position his work as nonthreatening: "there are no monsters in the closet, no dread doors that we must fear opening." The introductions of the sex and race parts of the book do the obligatory historical context-setting of emphasizing that old-timey patriarchy and chattel slavery were Actually Really Bad.