Once upon a time Martians and Venusians met, fell in love, and had happy relationships together because they respected and accepted their differences. Then they came to earth and amnesia set in: they forgot they were from different planets.

Using this metaphor to illustrate the commonly occurring conflicts between men and women, Gray explains how these differences can come between the sexes and prohibit mutually fulfilling loving relationships. Based on years of successful counseling of couples, he gives advice on how to counteract these differences in communication styles, emotional needs and modes of behavior to promote a greater understanding between individual partners. Gray shows how men and women react differently in conversation and how their relationships are affected by male intimacy cycles ("get close", "back off"), and female self-esteem fluctuations ("I'm okay", "I'm not okay"). He encourages readers to accept the other gender's particular way of expressing love, and helps men and women learn how to fulfill each other's emotional needs.