Having moved from industry to academia, I have breadth of activities which is unusual. There are several consistent underlying themes, in particular the behaviour of elastic waves in materials (with application to materials characterisation and materials testing) and the electronic structure of solids (especially defect centres). Each of these has been developed over several years. Interwoven with these have been both recurring motifs (such as the application of statistical methods to pattern recognition, classification, and extremal values) and isolated investigations (safety studies, applications of microwaves to characterisation of materials and to concrete demolition). Most recently I have been involved with investigations of the electronic structure of defects in the context of a quantum information processing scheme, and the propagation of elastic waves in fibre-reinforced metal matrix composites.