simulation, in which models described by different physics are coupled in order to bridge large length and time scales on supercomputers. Working initially with Eirik Flekkøy on foundations of the dissipative particle dynamics method and then with Rafael Delgado-Buscalioni, he was among the first to develop theoretical schemes which couple molecular dynamics and continuum fluid dynamics representations of fluids in a single simulation. Today, his work covers numerous applications of these methods in advanced materials and biomedical domains. The strong unifying strand in Coveney’s work which seeks to link the description of matter at the microscopic level with its macroscopic thermodynamic behaviour is manifest today in his work on the rapid, accurate, precise and reliable prediction of free energies of binding of ligands to proteins, a major topic in drug discovery. Coveney has noted that classical molecular dynamics is chaotic and to make robust predictions from it requires the use of ensembles at all times. This is a very practical manifestation of his earlier work on simpler dynamical systems, for which a thermodynamic description is possible using a probabilistic formulation. It has only become possible in the era of petascale computing, when supercomputers have grown to sufficient size to make calculations of ensemble averages feasible. The challenge of simulating chaotic systems on digital computers remains open today. Working with Bruce Boghosian and Hongyan Wang, Coveney showed that there are a variety of problems which arise when simulating even the simplest of all dynamical systems — the generalised Bernoulli map — on a computer. The IEEE floating point numbers can produce errors which are extremely large as well others of more modest scale, but they are each wrong when compared with the known exact mathematical description of the dynamics. In recent years, Coveney has been a leading player in the development and application of validation, verification and uncertainty quantification (VVUQ) to computer simulation codes across a wide range of domains. The VECAM Toolkit and later SEAVEA Toolkit provide a set of open-source, open-development software components which can be used to instrument any code so as to study its VVUQ characteristics. The methods his team has developed are aimed at the analysis of real-world codes of substantial complexity which run on high performance computers. The most recent research area within which Coveney has become active is quantum computing where he is specifically concerned with seeking to assess the feasibility of realising quantum