On the cover: HIV infection and its consequences continue as significant challenges for our times. The cover image invokes aspects of both initial infection, immune response, and lymphocyte death pathways. Although dark areas are also part of the artist's interpretation of this scourge, the dark patches are offset by the hopeful red ribbons that have become a widespread symbol of HIV awareness. An associated article by Massanella et al. appears in this issue. Cover design by Bärbel Beran [www.beran-design.de].