Andy formed Cresset in 2002. His ground-breaking research on comparing molecules in terms of their electrostatic potentials formed the scientific foundation of the company and has continued to underpin Cresset’s technical development. Andy’s work revolved around developing and improving the XED force field. The ideas behind this force field were originally introduced by Hunter and Sanders, JACS 1989, to model aromatic-aromatic interactions, and were extended into a full general-purpose force field by Andy (JCAMD, 1994). The XED model was developed with a special focus on accurate molecular electrostatics, including anisotropic charges on atoms and polarizability. It was the first major effort to move beyond the atom-centered charge model and did so not by placing explicit multipoles on atoms but by placing additional monopoles around them. This allowed it to correctly predict aromatic-aromatic stacking geometries and energies, hydrogen bonding and anomeric effects and the intermolecular interactions of small molecules, water and proteins. Not one to take up formal retirement, Andy’s latter work focused on understanding agonism and antagonism in adrenergic GPCRs, particularly β2. Andy was a founder member of the Molecular Graphics and Modelling Society (MGMS) in 1981, served as the first chairman and remained on the committee for many years. Andy passed away on 16th December 2019. His legacy is one of passion and drive for investigating realistic explanations for drug interactions with biological targets by computational means; of course, accompanied by wit and charm. Andy is sorely missed by all of us who had the pleasure and privilege of knowing and working with him.