From the back of the book
1866 Arizona, Confederate officer John Carter, Gentleman of Virginia, forever aged 30, wakes naked on Mars. Low gravity increases his speed and strength exponentially, so he impresses green alien Thark captors with fighting, wins high rank. He frees Dejah Thoris, Princess of red men in Helium, only to lose her to the Prince of opposing red Zodanga.
A PRINCESS OF MARS, whilst being a pulp science fiction classic borrows heavily from western fiction (the wild west adventure stories) and is somewhat spoiled by a pompous protagonist who can master any task he puts his mind to.
Luckily, the comic book thematic feel and off beat nature of the narrative redeems the story and keeps things a little tongue in cheek rather than hardcore science fiction (which it could have been, had the author wanted to world build and over-complicate what was a pretty entertaining story).
A PRINCESS OF MARS wasn't as good as I thought it would be but I still enjoyed it enough to want to read book 2. This time knowing what to expect from John Carter is likely to alter my expectation and enhance the reading experience.