During the two years since the publication of the first edition of this book, the global spread of human immudeficiency virus/acquired immudeficiency syndrome (HIV/AIDS) has continued. HIV was estimated by the World Health Organization (WHO) in 1993 to have at least 13 million individuals worldwide, with 1 million infected infected in the United States. HIV/AIDS in the United States has become the leading cause of death among men 25 to 44 years of age and the fifth leading cause of death among women of the same age group. Prevention of HIV infection remains a global challenge. Testing for HIV is the cornerstone for surveillance and prevention programs and for the provision of appropriate medical care for those who are infected. Such testing is equally essential to the search for effective antivirus drugs and vaccines. This second edition of AIDS Testing incorporates the most current thinking on test methodology and interpretation, some of which has changed considerably over the past two years. This edition also has been expanded to include a section consisting of six chapters on test applica- tions and a section consisting of four chapters on management issues. This edition, like the first, describes in clear terms all the complex ele- ments of testing, including applications, scientific principles, quality assurance, safety, and medical, ethical, and legal considerations.