Women make 80 percent of all purchasing decisions and are therefore undoubtedly the largest and most important consumer group, yet women have been poorly understood and badly served by marketing that has operated as if all customers are inherently the same. A deep understanding of the differences between men and women leads to more relevant, meaningful ideas that will contribute significantly to a brand's success. Derived from the latest research on gender, readers will learn that women judge and purchase goods and services by four main codes: altruism, aesthetic, ordering, and affinity. This essentially new approach provides the tools, clear constructs, and case studies to help companies take full advantage of the opportunities offered by gender-based marketing.