Planetary surfaces

This review paper has several aims: first, briefly to characterize planetary photogeology as a scientific discipline; second, to provide some sense of the rapid emergence of this field; third, to systematically review the literature over the past few years; and fourth, to identify the more significant problems for future analysis. To some degree, the four sections dictated by these goals speak to different audiences. Those unfamiliar with the progress in our understanding of planetary surfaces may be best entertained by a broad overview. Those involved in related science may find more useful the brief citations of the recent literature.