During the first few million years of our solar system’s history, magnetic fields were produced in the solar nebula. Perhaps concurrently or shortly thereafter, many planetesimals underwent differentiation and segregated into a metallic core and overlying silicate mantle. Secular cooling of these differentiated planetesimals facilitated core convection and the generation of dynamo magnetic fields. To understand the evolution of the solar nebula and characterize dynamo activity in small bodies, we conduct studies in meteorite paleomagnetism. These studies not only have the potential to understand the history of early solar system fields, but also processes that occurred on planetesimals including but not limited to impact cratering, hydrothermal activity, and the thermal evolution of planetesimal crusts.