The magnetic field is one of the fundamental physical properties of the Earth as well as of many other planetary environments. Being the signature of a variety of physical processes, it can provide, for instance, insights into core dynamics, mantle conductivity, crustal and upper mantle properties, and electric currents flowing in the ionosphere and magnetosphere. Due to the complexity of the Earth’s magnetic field, however, many of its features remain to be unveiled or better understood. A lot of progress remains to be done in order to disentangle the contributions of its different sources and extract information about their mechanisms and physical properties. For this reason, it is crucial that methodological advancements in magnetic field measurements (whether ground, airborne, marine, or satellite), in data processing, modelling techniques, geomagnetic indices and interpretation are continuously made. This session wishes to promote all efforts towards this direction. We solicit contributions that develop, introduce and employ innovative methodologies in the study of the Earth’s magnetic field in terms of any of its sources. Bearing in mind that the same methodologies can often be applied for the study of different planets and moons, we also welcome contributions dealing with the magnetic field of other bodies of our solar system. Hereby, we hope to promote mutually beneficial exchanges between the geomagnetism and the planetary communities.