Prof. Petr Heinzel is leading scientist at the Czech Academy of Sciences and full professor at Charles University in Prague. He was the director of the Astronomical Institute of the Czech Academy of Sciences. His research interest is solar physics and astrophysics in general, with focus on non-equilibrium spectroscopy of solar and stellar atmospheres. He was collaborating with Prof. Zdenek Svestka who co-founded the Springers's journalSolar Physics (P. Heinzel is member of the editorial board of this journal). The edited Topical Issue of this journal, reprinted in book form, is dedicated to memory of Z. Svestka (see Preface by the Guest Editors). Prof. Heinzel has received several awards from the Academy of Sciences, Czech Astronomical Society and Wroclaw University in Poland.

Prof. Lyndsay Fletcher is full professor at the University of Glasgow, UK. Her main interest is the solar physics and physics of solar and stellar flares, of which sheis an internationally highly recognized expert. Currently she leads the European project FP7 called F-CHROMA, devoted to solar flare research. Together with P. Heinzel, she co-organized an international conference on solar and stellar flares dedicated to Prof. Svestka and the edited Topical Issue ofSolar Physicsresulted from this meeting.