What is the meaning of differences and why are we so afraid of them? These decep-
tively simple questions are at the heart of this book. Of course, females and males
differ in some ways and are similar in others, but where are the differences and the
similarities, and how can we make sense out of them? Perhaps there are even more
fundamental questions that need to be asked first: Why is it important to know about
differences? Are answers even possible given the many ways that belief systems bias
the conclusions that we make and the decisions about what we want to know? All of
these questions have a long and turbulent history entangled with beliefs about the ap-
propriate roles of men and women and the political and economic ramifications of
the way we answer them. The questions and answers are philosophical, empirical,
political, historical, and interesting to large numbers of people both inside academia
and in the real world that exists beyond the ivy curtain. Those opposed to research on
sex differences fear that it will legitimize false stereotypes, obscure similarities, and
provide fuel for those determined to convince the world of the inferiority of females
or be used in ways that discriminate against males. As I write this preface, the new,
repressive government in Afghanistan has forbidden all girls and women from at-
tending school or working outside the home. I hope that this stunning act of discrimi-
nation will be history by the time you are reading this book. But, it does underscore
an important reality, the potential for the misuse of information on cognitive sex dif-
ferences is cause for concern; no wonder so many people are afraid of any research
that examines group differences.

In writing about such a sensitive and politically explosive topic, I have tried to
present the most recent findings along with some age-old questions about "male-
ness" and "femaleness" in as fair and unbiased way as possible. I wanted to go be-
yond the pop culture version of sex differences that is presented on talk shows and
in the usual array of books found in many book stores to provide a reasoned and

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