In memory of Will Steffen, 1947–2023

Will Steffen’s death has prompted the present article that attempts to summarise the many aspects of his contribution to our understanding of Earth System science, his role as an outstanding leader and communicator and the affection and respect he earned from his many colleagues, friends and associates. Personal recollections of Will from his time as Executive Director of the International Geosphere-Biosphere Programme (IGBP) and as contributor to and fellow editor of the Anthropocene Review are also included.