The crust of the Moon, like that of Mars, is locally magnetized. The origin of this magnetism is currently under debate but the most widely accepted hypothesis is that the Moon used to have a dynamo at some point in its early history, which then shut off. However, numerical studies, simulating the lunar dynamo, cannot explain the findings of paleomagnetic studies on Apollo rock samples. The small size of the Moon’s core should not be able to generate the magnetic field intensity that paleomagnetic studies report. Moreover, little is known about the origin of the various crustal magnetic field signals as most of them do not correlate well with visible geological features. The study of the lunar magnetic field is therefore an active field of research.