Pictures returned by the Mariner 9 and Viking missions yield a wealth of new information about Mars. As a result, two new books have appeared recently dealing exclusively with Mars, one by Michael H. Carr (The Surface of Mars, Yale University Press, New Haven, Conn., 1982) and the other, discussed here, by Victor R. Baker. Both are timely pieces giving comprehensive summaries of the newly acquired knowledge. Whereas Carr's book discusses the general geology of Mars, Baker's book concentrates on the geomorphology with emphasis on channels. Both books are welcome additions to the planetary literature.