Arnold, who has written for younger readers on electric fish and bird parenting, seems to be a little out of her depth in this complex and touchy subject. She plods through the basic facts and definitions with explanations that do not explain and historical and other material that dampens reader interest because it is not ordered along any route of natural curiosity or rational inquiry. Later, in the tricky areas of how sex hormones affect behavior, she cites a number of interesting experiments on animals. However, they appear here as in isolation, without the considered context that would be provided, say, by the Silversteins; and Arnold carelessly makes too much of them. For example, she jumps from ""In most cases, female [animals] develop faster and live longer than males"" to ""currently in the United States the life expectancy for men is 68.7 years, and for women it is 76.5 years."" This is poor logic, poor science, and abysmal pedagogy. Arnold's generalizations about the differences between men's and women's brains and areas of intelligence also present controversial assumptions (based on performance), as known fact. All in all, though this might be welcomed for its coverage, it is more likely to muddle than clarify the issues.