Iain D. Stewart is a Research Fellow at the Global Cities Institute, University of Toronto, Canada. He has two decades of experience in heat island research and has taught courses in urban climatology to engineers and architects. The mainstay of his work is both a critical analysis of heat island studies globally and the development of scientific standards for assessing urban temperature effects at the local scale. A major output of his work is the widely used Local Climate Zone classification system. For his advances in the field, Iain has twice received the William P. Lowry Memorial Award from the International Association for Urban Climate (IAUC).Gerald Mills is an Associate Professor in the School of Geography at University College Dublin, Ireland. He has three decades of experience in urban climatology and is a co-author of a modern textbook (Urban Climates) on the field. His work focuses on the development of an urban climate science that has a coherent body of knowledge and associated tools to enable its application to cities globally. He is a former President of the International Association for Urban Climates (IAUC) and of the Geographical Society of Ireland.