"Respiratory infections are one of the most common causes of morbidity and mortality worldwide. As we enter the twenty-first century, several landmark events are unfolding in the area of respiratory infections. Some of these, by assuming the form of formidable disasters, have abruptly claimed lives and led to economic loss. Examples include severe acute respiratory syndrome (SARS) and bird and swine influenza. Viral and bacterial resistance to currently available antimicrobial drugs is thwarting efforts in the management of influenza and pulmonary sepsis. Newer and emerging viral lung infections are seen more frequently in clinical practice, including post-transplant viral infections other than cytomegalovirus and Epstein-Barr virus. The frequency and diversity of serious fungal infections are increasing. Persons who are severely immunocompromised are particularly vulnerable to infection from unusual molds and yeasts that are often found naturally in the environment. Other respiratory infections pose continuous health care challenges. Examples include the changing demography of tuberculosis (TB) and emerging deadly drug-resistant forms of TB worldwide. Pediatric TB and elderly TB are on the rise and the problem of coinfection with HIV is proving difficult to diagnose and manage. Anti-tumor necrosis factor (TNF)-a therapy for autoimmune conditions results in reactivation of TB. In addition, occupational lung diseases due to airborne microbes constitute another problematic issue. Protozoal and helminthic lung infestations continue to be important clinical problems in many parts of the world. This issue of Infectious Diseases Clinics of North America is aimed at giving an up-todate and comprehensive overview of emerging respiratory infections in the twenty-first century through 14 articles written by authoritative experts from all around the globe." - p. xiii