William Ian Axford was born and educated in New Zealand, receiving his ME and MSc degrees from Canterbury College of the University of New Zealand in 1956. He completed his PhD at Manchester University in 1960 and spent the following year at Cambridge University before moving to the Defence Research Board of Canada. From 1963 to 1974 he held professorships at Cornell University and the University of California at San Diego. From 1974 to 2001 he directed the Max Planck Institute for Aeronomy in Germany, with two three-year periods of leave in New Zealand in 1982–85 and 1992–95. Ian Axford was one of the greatest plasma physicists of the space age. He made fundamental contributions to a wide range of topics in the fields of space physics and astrophysics, including the dynamics of the Earth’s magnetosphere, the magnetic field reconnection process, the Sun’s atmosphere and the formation and evolution of the solar wind, the interaction of the solar wind with the interstellar medium and with comets, cosmic ray propagation and modulation in the Solar System, the acceleration of cosmic rays in supernova shocks, and the use of robotic spacecraft in the exploration of the Solar System. Ian was also a remarkable science administrator, completely restructuring the Max Planck Institute for Aeronomy and transforming it into one of the world’s leading space and atmospheric research institutes. He was a great advocate of international collaboration in science, and reinvigorated several flagging institutions such as the European Geophysical Society and the International Council of Scientific Unions Committee on Space Research.