This issue of Clinics in Laboratory Medicine, entitled Respiratory Viruses in Pediatric and adult Populations, is Guest Edited by Alexander J. McAdam MD, PhD, and includes: Developments in Specimen Collection and Tissue Culture for Respiratory Viruses; Nucleic acid amplification assays for respiratory viruses; Emerging molecular assays for respiratory viruses; Drug Resistance in Influenza Virus; Quantitative assays for adenovirus; RSV vaccine development; Human Metapneumovirus; and Recently discovered coronaviruses.