Cover image: A microdiamond from the ultra-high-pressure rocks of the Erzgebirge massif in Germany. These metamorphic rocks, originally from the earth's crust, were subducted to the deep upper mantle before returning to the surface. Advanced analysis of the interior of microdiamonds reveals details of the environment in the mantle. See the article by Dobrzhinetskaya et al. on pages 9128–9132. Image courtesy of Larissa Dobrzhinetskaya.