Anne Nédélec and Jean-Luc Bouchez are Professors in Earth Sciences at the University of Toulouse. Both are based at the Observatoire Midi-Pyrénées (Géosciences Environnement Toulouse). Anne is a petrologist, specialist of Precambrian Geology. Jean-Luc, a specialist in rock deformation, participated in the development of structural studies in magmatic rocks. Both have a broad experience in laboratory and field studies in Africa, Madagascar, Brazil, Iran, and France, among others. Peter Bowden has been Professeur Invité in the Département de Géologie at Université de Saint Etienne since 1998. He was Editor-in-Chief of the Journal of African Earth Sciences from 1993 to 2001, and Senior Lecturer and co-ordinator for the BSc Geochemistry degree at the University of St Andrews, Scotland, from 1987 to 1998. He is a specialist in African Geology and an expert on A-type granites. =