About the Cover: Engineering of carbon nanotubes with an electron beam. The displacement of atoms from hot carbon nanotubes by knock-on collisions with high-energetic electrons leads to a variety of structural alterations. The electron micrographs show the removal of a few atoms from the outermost layer of a multiwall nanotube (top left), the bending of a nanotube under irradiation (top right), the local transformation of a bundle of single-wall nanotubes into a multiwall nanotube (bottom left), and the transformation of a section of a nanotube into a spherical carbon onion (bottom right). J. X. Li and F. Banhart, p 1143. View the article.