My verdict: I really appreciate that the events in this book were foreshadowed in the previous book, rather than being dumped on us without warning—it helps my suspension of disbelief. However, a six-foot man defeating hundreds of ferocious thirteen-foot monsters in a single battle does not. Burroughs' favorite themes come out again in this one: nobility of blood and character, as well as the noble savage. However, he also takes on organized religion—though the idea that the same subterfuge could be carried out almost perfectly duplicated for so many tiers was hard to swallow. Burroughs changes the speech of the Martians (and John Carter's speech) in this one to make it sound more alien , however, midway through the book this 'accent' disappeared. He also employed unexplainable, fantastical coincidences which only frustrated me as a reader. The book ends on a tragic cliffhanger, like its successors, The Lord of the Rings and Star Wars, to make sure you read the third book.
The Barnes and Noble typos continue, at one point referring to a battle between black Martians and white Martians as being "between the blades and whites". If you decide to read this book, get it somewhere else.
 Read my review here.
 See http://en.wikipedia.org/wiki/A Princess of Mars#Writing.
 He does this primarily by replacing many conjunctions of the verb to be with the infinitive and to a lesser extend using were (as a subjunctive form) to replace the conditional would be.
 Thuvia (introduced in this book) discovers that she can sooth banths simply by talking to them. No other Barsoomian (Martian) can do this. Where did this ability come from? Thin air. But it's crucial to the plot of this book and its sequel. Burroughs also never explains why, even before his advent to Mars, John Carter lived hundreds of years and never aged.
 Read my review here.
 e.g. you can read it here at Project Gutenberg.
The Atmosphere of Mars is by the Viking 1 Orbiter (NASA) and exists in the public domain. It is available at http://commons.wikimedia.org/wiki/File:Mars atmosphere.jpg. Note that you can see the Galle Crater, which resembles a smiley face.