Articles in this monograph examine key issues in combined drug and alcohol use. The first chapter discusses clinical and research evidence about the physical and psychological effects of various drug and alcohol combinations. Chapter Two presents findings about usage patterns of alcohol and drugs. The impact of alcohol use in a treatment setting is explored in the third chapter; alcohol problems in a methadone maintenance program are discussed, including recognition and diagnosis and the development of alternative treatment protocols. Chapter Four provides an in-depth examination of the sedative-alcohol abuser. The relationships between different facets of crime and patterns of substance abuse are examined in Chapter Five. The sixth chapter reports on a followup sample of 1,409 clients of a drug abuse treatment program and examines alcohol use and its relationship to illicit drug use and treatment before, during, and after treatment. The final chapter examines the common elements underlying heroin/alcohol abuse. Demographic and psychosocial variables of substance abusers are explored, along with the sequential use of alcohol and heroin. (Author/NRB)