Jan Zalasiewicz is a Professor of Paleobiology at the University of Leicester and Chair of the Anthropocene Working Group. His research interests include mudrock processes; early Palaeozoic and Quaternary stratigraphy and sedimentology; and stratigraphic analysis, notably the study of the Anthropocene concept. Colin N. Waters is an Honorary Professor in the Department of Geology at the University of Leicester, and secretary of the Anthropocene Working Group with a central role in coordinating activities of the Working Group members. He recently retired as a Principal Mapping Geologist at the British Geological Survey, where he specialised in geological mapping of the UK and parts of the Sahara Desert, and stratigraphical analysis, principally of the Carboniferous and Anthropocene. Mark Williams is a Professor of Palaeobiology at the University of Leicester. He is interested in the evolution of the biosphere over geological timescales, with an emphasis on understanding the rate and degree of current biological change. He was the first secretary of the Anthropocene Working Group from 2009 to 2011. Colin Summerhayes is an Emeritus Associate of the Scott Polar Research Institute at the University of Cambridge. He is a marine geologist and oceanographer with expertise in the role of climate in forming marine sediments, and in interpreting the history of climate from sedimentary records. He is a former Manager of the Stratigraphy Branch of the Exploration Division of BP Research, and former Director of the Institute of Oceanographic Sciences Deacon Laboratory, Wormley.