About the cover: After deposition of a fluorescent macromolecule in the airways, migratory dendritic cells can be found transporting their fluorescent cargo to the mediastinal lymph nodes. This figure is reproduced by permission from K. Y. Vermaelen, I. Carro-Muino, B. N. Lambrecht, and R. A. Pauwels: Specific migratory dendritic cells rapidly transport antigen from the airways to the thoracic lymph nodes (J Exp Med 2001;193:51-60). For more information, see article by Vermaelen and Pauwels beginning on page 530.