More and more, writers are emphasizing the basic similarities of sexual response in men and women. We see this as a positive trend away from the once-popular notion that great differences exist between the sexes—an opinion that undoubtedly helped create a big market for many "love manuals" designed to inform readers about the mysteries and complexities of the "opposite sex." Now we know that much can be learned about our partners by carefully observing our own sexual patterns. Nevertheless, there are some real and important primary differences. In the following pages we outline and discuss some of them. Readers may also find the Spotlight on Research box, which describes a cross-cultural survey of sex differences in sex drive, to be of interest.