Dr Hobbs is distinguished for his contributions to structural geology and rock mechanics. He has pioneered the application of small-scale structure analysis to structural geological problems in Australia and established himself as the most prominent figure nationally in structural geology and a very well-known one internationally. His experimental work on the role of water in the deformation and recrystallization of quartz is classic and he has had a very important influence in the deformation field in emphasizing the role of defect chemistry. Finally he has complemented his experimental and field studies, with perceptive numerical modelling of geological problems, especially those involving the development of crystallographic preferred orientations in deformed rocks and the genesis of shear zones and their behaviour.