Enrico Gnecco is a Senior Scientist at IMDEA Nanoscience, Madrid, where his research focuses on friction phenomena on the atomic scale, controlled manipulation of nanoparticles and theoretical bases of nanotribology. Ernst Meyer is Professor of Experimental Physics at the University of Basel and module coordinator in the NCCR for Nanoscale Science. He is a former Chairman of the European Science Foundation collaborative network 'Nanotribo'.