My research career has to a major extent consisted of applying geophysics and scientific drilling to better understand the structure and composition of the continental crust. At the beginning, in the late 1980s, I was fortunate enough, as a PhD student, to be involved in the Siljan Ring Deep Drilling project in central Sweden. The discovery that mafic dolerite sills generate the observed high amplitude reflections observed on the surface seismic data has been important for studies of the source of crustal reflectivity, impact mechanics, and raised questions about dolerite intrusion mechanisms. This combination of geophysics and scientific drilling has been a cornerstone in many of the subsequent research areas.