AbstractThis special issue of physica status solidi (b) entitled “Frontiers in Molecular‐Beam Epitaxy toward Novel Devices” with 27 contributions from leading semiconductor scientists has been prepared to honor Klaus H. Ploog, Paul Drude Institute for Solid State Electronics Berlin, on the occasion of his 65th birthday.The cover picture shows an azimuthal reflection high‐energy electron diffraction (RHEED) scan of a 6.5 monolayer thick MnAs film on GaAs [1] overlaid on a GaAs wafer. The diffraction pattern is a cut through the reciprocal lattice of the epitaxial MnAs film, reflecting the hexagonal structure of MnAs. The growth of MnAs by molecular‐beam epitaxy and its structural and magnetic properties have been extensively studied under Klaus Ploog's directorship of the Paul Drude Institute. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)