J. Theo Kloprogge, MSc in Geology, PhD in Geology/Chemistry, is currently Adjunct Professor at the Department of Chemistry, College of Arts and Sciences, University of the Philippines Visayas, Philippines. From 2014 till the end of 2024, he was an Honorary Senior Fellow at the School of Earth and Environmental Sciences, University of Queensland, Australia. He has been teaching analytical chemistry, inorganic chemistry and mineralogy/crystallography for many years. During the past 30+ years Dr. Kloprogge has been working as a mineralogist (in particular clay mineralogy) and spectroscopist. The results of this work have been published in nearly 300 papers in international peer reviewed journals as well as in a number of book chapters (including Dev. Clay Sci. Vol. 7), 6 books (as author and/or editor, including Dev. Clay Sci. Vol. 8) and 1 patent. Barry J. Wood, BSc Chemistry (Qld), PhD Materials Science (UNSW), is Scientific Manager for X-ray Photoelectron Spectroscopy in the Centre of Microscopy and Microanalysis (CMM) at the University of Queensland (UQ). He has 35 years’ experience in X-ray Photoelectron Spectroscopy and, prior to joining the CMM, was manager of the Brisbane Surface Analysis Facility in the Department of Chemistry at the University of Queensland where surface analysis and consultation for industry was carried out on a daily basis. He has also been involved with a host of research groups within UQ, Queensland University of Technology, Griffith University, The University of NSW, The University of Melbourne and North-West University Potchefstroom South Africa, which has resulted in co-author of 74 papers in international peer-reviewed journals. He was, for many years, Standards Australia’s representative for ISO TC201 - Surface Chemical Analysis.