Impact cratering is a powerful and ubiquitous force in creating, modifying, and destroying planetary surfaces. Though the Earth maintains an incomplete record of its own bombardment, the ancient rocks of the Moon, Mars, and the asteroids preserve abundant evidence of impact craters and their products that reflect how their surfaces have evolved over 4.5 billion years. I will discuss my ongoing investigations of a diverse group of planetary materials and their use in inferring the impact history of the inner solar system, the composition of bombarding objects and planetary targets, and the potential effects that impacts have had on the biotic evolution of the terrestrial planets.