The magnetic field of the Earth is dynamic and is an important property of the planet. The study of its more significant spatial and temporal features is fundamental to understanding the past and the present state of the planet, and, importantly, its evolution into the future. There are several open questions that deserve more attention, for example, the present rapid decay of the field that could be a precursor to an excursion or a reversal, the geodynamo properties that are still hidden in the outer core, the existence in the present field of a large magnetic depression, the South Atlantic Anomaly, etcetera. This session is open to presentations concerning these questions and others related to the dynamics of the planet, the change of the Earth's magnetic field through its history and at the present time, together with possible consequences for life.