About the Author: Dr. Celso de Sousa Figueiredo Gomes (retired) is a former Professor Cathedratico at University d'Aveiro, Portugal. He was Assistant Professor (1961 - 1967) at the Mineralogical and Geological Museum of the University of Coimbra, teaching Crystallography, Mineralogy, Petrology, and Geology, and he was Chief-Geologist of the Geological Survey of Angola and Assistant Professor at the University of Luanda, Angola (1968 - 1974). In 1964 he began his study of Soil and Clay Sciences at the Instituto de Edafologia e Agrobiologia Vegetal of the Consejo Superior de Investigacion Científica (Madrid), and continued in Aberdeen, Scotland, at the Macaulay Institute for Soil Research. In 1979 he received a PhD in Materials Science from the Leeds University, United Kingdom. He is the author and co-author of over 500 scientific papers, and the author and co-author of 21 books and 5 chapters of scientific books. He has organized various National and International Conferences.
Since his retirement (2003) Dr. Gomes is a researcher of the Research Centre "GeoBioTec" financed by the Portuguese Foundation for Science and Technology of the Ministry of Science, Technology and Higher Education. Dr. Gomes presently is member of the following scientific societies: AIPEA (Association Internationale Pour L'Étude des Argiles), Mineralogical Society (United Kingdom), Clays and Clay Minerals Society (United States of America), Sociedad Española de Arcillas (Spain), Clay Science Society (Japan), Sociedade Portuguesa de Cerâmica e Vidro, Sociedade Portuguesa de Hidrologia Médica, and Global Scientific and Advisory Council of the World Health and Wellness Tourism Association (WHWTA). In 1995 he founded APA (Associação Portuguesa de Argilas), an affiliate of ECGA (European Clay Groups Association) and AIPEA, being the President of ECGA (2007 - 2011).
Dr. Michel Rautureau (retired) began working in 1958 at the French National Centre for Scientific Research's "laboratoire de synthèse atomique et d'optique protonique" a facility dedicated to electron microscopy of clay minerals and cell biology. He worked under the direction of Professor Claude Magnan, author of the famous "Traité de microscopie électronique". Dr. Rautureau received his PhD in 1972; his theses work on the crystalline structure of sepiolite, a fibrous clay mineral, and was soon recognized as an authority on clay minerals. He, with Simonne Caillère and Stéphane Hénin authored "Minéralogie des Argiles" a major reference in the subject of the mineralogy of clay minerals and the first book to present their global classification. Dr. Rautureau is a member of Groupe Français des argiles (GFA), Association Internationale Pour L' Étude des Argiles (AIPEA), French society of electron microscopy, French society of Mineralogy, French society of geology, Sociéte botanique de France, Association Française pour l'avancement des Sciences (AFAS), and a member of the administrative council for Section Française de l'Institut International de la Conservation (SFIIC).
