My research is mostly concerned with Earth’s magnetic field. I am particularly interested in decadal to million year variations in the geomagnetic field and how the changing structure of the magnetic field and events like geomagnetic reversals can inform scientists about processes in Earth’s deep interior. I also use magnetic observatory and satellite magnetic field observations to study the electrical conductivity of Earth’s mantle. I am an active proponent of the development of databases and cyberinfrastructure allowing electronic access to paleomagnetic and rock magnetic data.