During the 20th century alcohol and alcoholism have emerged as a problem with global health implications. In Westernized countries > or = 50% of adults can be classified as alcohol consumers. For most people, drinking is a safe, pleasurable experience with minimal health consequences. However, about 10% of alcohol consumers will at some time experience serious health problems related to their drinking habit. Persons at risk of drinking problems cannot be reliably identified in the population--a fertile area for additional research. At present, the World Health Organization estimates that > 15 million people are disabled as a result of alcohol use, making it the fourth leading cause of worldwide disability. The challenge for the 21st century is to reduce the impact of alcohol-related disease by measures including: * Identification of high risk individuals. * Social control. * More effective treatment modalities for people addicted to alcohol.