This paper provides an introduction to a series of articles reporting results from the EU concerted action "Gender, Culture and Alcohol Problems: A Multi-national Study" which examined differences in drinking among women and men in 13 European and two non-European countries. The gender gap in alcohol drinking is one of the few universal gender differences in human social behavior. However, the size of these differences varies greatly from one society to another. The papers in this issue examine, across countries, (1) men's and women's drinking patterns, (2) the prevalence of men's and women's experience of alcohol-related problems, (3) gender differences in social inequalities in alcohol use and abuse, (4) gender differences in the influence of combinations of social roles on heavy alcohol use, and (5) how societal-level factors predict women's and men's alcohol use and problems on a regional and global level. Country surveys were independently conducted and then centralized at one institution for further data standardization and processing. Several results indicated that the greater the societal gender equality in a country, the smaller the gender differences in drinking behavior. In most analyses the smallest gender differences in drinking behaviour were found in Nordic countries, followed by western and central European countries, with the largest gender differences in countries with developing economies.