In the late 1800s, John Carter, a fine Virginia gentleman whose slaves worshipped him, went into sort of a coma and woke up on Mars. Mars is full of warriors (after all, it's named after the god of war) and they're surprised by how powerful he is, since he's trained to a higher gravity. One group, green and nekkid, captures him and he works his way up in their hierarchy. The Martians have done an excellent job of capturing and distributing water, other than that they need a finer grade of distribution, and they know how to capture the sun's rays (not electricity, the rays). Then he found out about a scientist-type of Martian and the beautiful daughter of the leader, Dejah Thoris. Who was also green and nekkid, and, as all Martians, reproduced by eggs. He and Dejah work to get together and then to be safe, but it's a tough planet out there.
I don't like these books, and not just because of the silly/stupid science and florid language and style. I like books with a little more to them than wars and lust. Lots of people really like them, though, because the newest edition we had there was the 41st.