Isabella (Lady Trent) continues her memoirs with the story of her second expedition, this one to the savannahs and jungles of the south. There she encounters several different civilizations and a new type of dragon, and discovers much about herself and her world. 
 In my reviews of second-in-the-trilogy books, I often discuss how difficult middle books are to get right, and excuse a lot of weaknesses because of these difficulties. No such discussion or excuses are necessary for Tropic of Serpents, which surpasses even A Natural History of Dragons in depth, quality, and character development. The Lady Trent who emerged from Vystrana is a more mature, more culturally understanding, more self-aware person than the one who went in. The disdain with which she looked on the Vystrani natives in the previous book has given way to careful study of differing cultures and even more careful attempts to see things their way. While she still stumbles in her relations with the non-Scirling peoples, she is aware of these stumbles and works hard to amend them and keep from repeating them. She embraces differences rather than trying to change them or thinking herself superior to the tribespeople she interacts with in the deepest jungle. 
 Even the character flaws that mar Isabella early in the book, specifically her relationship with her young son, start to smooth toward the end. She recognizes that she has a responsibility as a widowed mother, and while she does not give up her calling or her desire to travel, she will, presumably, take his needs into account much more than she had been. Likewise, her frustrations about how her family and the public treat her and her son get aired, and they are valid complaints that help the reader understand and sympathize with her more than otherwise. 
 Even Brennan's worldbuilding is deeper and more impressive in The Tropic of Serpents than it was in A Natural History of Dragons, which helps to create the impression of a more worldly-wise and perceptive narrator. 
 Highly recommended.