Epoxy resins are versatile raw materials for industrial products, such as windmill blades, aerospace parts, generator encapsulations, microelectronics, and structural adhesives. Stephan Sprenger on page 1421 gives an overview of the state of research, with a focus on mechanical properties. In a cured epoxy resin, nanosilica should be monodispersed. Most research shows well-dispersed nanoparticles and claims that improvements are a result of the good dispersion. The cover image shows agglomerates in cured epoxy resin, where the agglomeration is induced upon cure with an additive.