Professor Thomas has an outstanding international reputation on the borderline of nuclear and particle physics. He developed an understanding of pion-nucleus interactions and nuclear structure based initially on a three-body calculation of the pion-nucleon-nucleon system. His cloudy bag model describes the nucleon as three confined quarks obeying chiral symmetry through interaction with a pion cloud. It predicts important nucleon properties such as the neutron charge distribution and describes the nucleon in the presence of other nucleons which helps to understand the apparent dependence of nucleon structure on the nuclear environment.