The front cover picture, designed by Yannis Boultadakis-Arapinis illustrates the concerted and step-wise reaction mechanisms that might be encountered during the insertion of metallo-carbenes into inert CH bonds. In their article, Lecourt, Gandon and co-workers describe the influence of short-distance and long-range electronic effects on the mechanism and stereoselectivity of the insertion of Rh(II)-carbene. A fine-tuning of the reactivity of the CH bond can thus induce a switch from a concerted and fully diastereoselective mechanism with a Curtin-Hammet-like kinetic profile, to two fully disconnected step-wise and stereoselective processes. Details can be found in the full paper on pages 2493–2505 (M. Boultadakis-Arapinis, V. Gandon, E. Prost, L. Micouin, T. Lecourt, Adv. Synth. Catal. 2014, 356, 2493–2505; DOI: 10.1002/adsc.201300984).