The lunar cratering record provides valuable information about the late accretion history of the inner solar system. However, our understanding of the origin, rate, and timing of the impacting projectiles is far from complete. To learn more about these projectiles, we can examine the crater size–frequency distributions (CSFDs) on the Moon. For example, by comparing the shape of lunar CSFDs with the size–frequency distributions of potential projectile families, like different groups of asteroids, comets, or even ejecta projectiles from the giant impact that formed the Moon. We can potentially identify the origin and composition of the impacting projectiles in the inner solar system. In addition to helping identify these projectiles, the shapes of lunar CSFDs are particularly important for determining crater-based relative and absolute ages of surfaces, because CSFDs are used to define the so-called lunar “production function” (PF) from which these ages are calculated. Also, if any changes to the PF are observed over time, this indicates that more than one impactor population may have formed the lunar cratering record.