A tribute to Alan Soper - foreword by the editors FOREWORD

This special issue of Molecular Physics is a collection of papers to mark the retirement and honour the remarkable scientific contributions of Dr. Alan Kenneth Soper FRS. Over an active research career spanning more than four decades, Alan has developed state-of-the-art neutron-scattering instrumentation, experimental and analytical techniques, and computational methods that collectively have transformed our understanding of the atomic and molecular structure of liquids and other structurally disordered systems. The summary leading to his election as Fellow of the Royal Society in 2014 says it all: Alan Soper is distinguished as the world-leading experimentalist on the structure of water and aqueous solutions, and an internationally outstanding expert on the structure of liquids in general. Besides making major and seminal contributions to the study of water and other aqueous systems, including complex systems of high chemical and biological importance, he has been influential in studies of many other liquids and glasses, and has developed novel diffraction instruments and techniques that have revolutionised the field. He has also pioneered the wider use of computer simulation as a tool for building three-dimensional models of the disordered states of matter based on measured data