Cover image: Simulated pandemic influenza outbreak in the United States, based on daily entry of a small number of infected individuals through 14 major international airports, at days 0 (Top), 65 (Middle), and 85 (Bottom). Prevalence of symptomatic cases at any point in time is indicated on a logarithmic color scale, from 0.03% (green) to 3% (red) of the population. With no mitigation strategies implemented in the simulation, an infection attack rate of 43.5% is predicted. See the article by Germann et al. on pages 5935–5940.