The opening article compares AIDS knowledge, needle sharing patterns, needle hygiene, and suggestions for an AIDS education or intervention program among IVDU's in drug-using networks of Los Angeles and San Francisco. Another study compares the demographics, drug use practices, and HIV (human immunodeficiency virus) seroprevalence on in-treatment and out-of-treatment samples of San Francisco IVDU's, followed by a report on preliminary findings from an ongoing evaluation of street-level AIDS prevention and education efforts. An article reports on an ongoing study of risk factors for AIDS among 230 clients in a New York hospital's methadone maintenance treatment program. The program did achieve some reduction in IV drug use with a high potential for AIDS transmission. The concluding article examines the physiological, psychological, cognitive, and cultural bases for the link between alcohol and drugs useand disinhibited sex, which can transmit the AIDS virus. All the articles document the need to increase preventive strategies which do show promise in their ability to reduce behaviors known to increase the risk of AIDS transmission. For individual articles, see NCJ-110615-19.