Nature Geoscience has compiled a special Focus on planetary science offering a glimpse of what we know and don't know. UA planetary geologists are authors of two of the overviews:
Did an impact blast away half of the martian crust? pp412 - 414
H. J. Melosh, doi:10.1038/ngeo237
The methane cycle on Titan - pp159 - 164
J. I. Lunine & S. K. Atreya, doi:10.1038/ngeo125