Professor Gregory Hartland was a Guest Editor for the themed issue on "Optical Studies of Single Metal Nanoparticles" that recently appeared in Physical Chemistry Chemical Physics (Volume 15, Issue 12, 2013). Co-editors for the issue were Hiromi Okamoto (Institute for Molecular Science, Okazaki, Japan), Michel Orrit (MoNOS, Huygens Laboratorium, Universiteit Leiden, The Netherlands) and Peter Zijlstra (Department of Applied Physics, Eindhoven University of Technology, Eindhoven, The Netherlands). This issue brings together papers from groups around the world who are working on plasmonic effects in single nano particles.