This is the second in the Enchanted Forest Chronicles. Ignore all the listings of it as first, and read Talking to Dragons first. That was published first, and this works better as an after-the-fact explanation.
But we have Cimorene, your typical princess nowadays, who doesn't want to do anything princessly, who runs away to be a dragon's princess instead of marrying the chosen prince -- or, for that matter, waiting to be abducted.
Her adventures wind on from there -- involving her offering a handkerchief to a dragon who reminds her of her great-uncle, cooking chocolate mousse, a prince turned to stone and yet alive, Cimorene claiming to have twisted her ankle, gathering feverfew, organizing a library with some works in Latin, a witch with cats and cider, and much more.
Light and frothy -- not to be taken too seriously.