16 Pags. This article as a Preface by the Editors belonging to a special issue of Catena titled "Geoecology in Mediterranean mountain areas. Tribute to Professor José María García Ruiz". The definitive version is available at: http://www.sciencedirect.com/science/journal/03418162 ; The origin of this special issue arose from a scientific meeting held in Logroño (Spain) in October 2014, under the theme Geoecology in extreme environments: mountains and semiarid areas ( Arnáez et al., 2014). The main motivation of the event was to recognise, on the occasion of his retirement, the outstanding contribution of Prof. José María García-Ruiz to the progress of Geoecology in Mediterranean mountain areas. Prof. García-Ruiz (Zaragoza, 1949) was lecturer, between 1974 and 1987, at the University of Cáceres and La Rioja. As staff Scientist and later Professor at the Spanish National Research Council (CSIC), he was Head of the Pyrenean Institute of Ecology (IPE-CSIC) (1987–1990) and Head of the Department of Global Change at the same institute, President of the Spanish Society of Geomorphology (1994–1996), besides a productive and tireless researcher. He has published more than 300 scientific articles, one third of them in international journals, and more than 35 books. He has participated in 40 research projects funded by the European Commission, Spanish and regional governments. With his enthusiasm and dedication he has inspired and encouraged a wide number of geographers and geomorphologists, including 10 PhD students and a great number of collaborators, most of them now working at different Universities and Research Centres around the world. ; Peer reviewed