Writers of fantasy who seek to move beyond some of the more parochial stereotypes of the genre would do well to look at these three books in particular, because Carey does an admirable job of establishing the sociology of the world. She evades the common trap that fantasy writers fall into when setting up epic story lines with clearly opposed forces because she does not settle for making any people, race, or army into a faceless mob of malevolent opponents. They are all nuanced and, for those who have a background with medieval history, they are recognizable-but-fantastically-altered.
Anyone who worries that "politically correcting" the fantasy genre will weaken it will find the opposite to be true here, as well. By creating peoples with conflicting wants and needs, clear stratification of classes within the society, and a complex array of tribal/national loyalties and personal ambitions, Carey weaves a much more realized, complex world than most sword-and-sorcery authors could dream of, using the fault lines created by the intersections of race, class, religion, and gender to create opportunities for more drama.
The result is the introduction of complex sub-plots that bring several other genres to bear at times throughout the books. The first novel, Kushiel's Dart, is essentially an erotic spy romance with a few large-scale war scenes woven throughout and a hefty amount of religious exposition establishing the ethos that governs Terre D'Ange and its citizens. It does a fair job of establishing an explanation for the religious prostitution and indentured servitude that plays such a large role in the series, but there are times when it feels a bit like heavy-handed explanation.
The second and third books, Kushiel's Chosen and Kushiel's Avatar, are the real treats. With the sociology and religion of Terre D'Ange already established, these novels catch fire and rush the reader through several states in an alternate medieval Europe where Terre D'Ange is constantly threatened along every border by forces that envy its prosperity and success. It is undermined from within by the ambitions of its aristocracy, whose racism and cultural chauvenism are not just the "other foot" that falls to show us that Carey is uninterested in utopia, but also the beginnings of their own undoing.
In these later books, there is still a hefty component of eroticism, but that becomes a part of the characterization of Phedre, the books protagonists, and not so much a motivating force for the plots, which move more and more into court intrigue and mystic quests.
All of these features make this series compelling reading for both genre fans and would-be writers, but don't expect total perfection. Carey does a fine job of overcoming many of the fantasy genre's more problematic elements, but this is both fantasy and her fantasy, and some of the components of cultural chauvinism and colonialism do show through, particularly in the way that Phedre continuously comments on the beauty of the D'Angelines (who are basically French/Swiss/etc. central Europeans) as being a gift from the gods making them objectively beautiful in an otherworldly way.
While she does still linger over sensuous descriptions of other peoples throughout the series (and in the later Naamah trilogy she dispenses with D'Angeline protagonists and comments on the arrogance of this cultural chauvinism), this motif does begin to rub me the wrong way at times. There's also the issue of the way that the middle-eastern kingdoms' attitudes towards women are rendered. Mostly, they draw from history without producing too much caricature, but the problem is that they are not as fully realized as most of the other societies in the books. The Ummaiyat (the people of the Arabian peninsula) are only featured as background (the books never take us there), and Kebbel-im-Akkad, the nation comprising most of the area that is Palestine, Lebanon, Israel, Iraq, and Iran, is only presented in brief. This provides us only a cursory glance at the courtly behavior for the peoples of this nation, with none of the richness, complexity, and class consciousness that we are treated to when Phedre is travelling in Africa or among the European nations in the books.
These books are a noble attempt, though, at pulling fantasy out of its traditional problems, and well worth reading for that. Later additions to the D'Angeline books continue the trend here and improve on it, continuing to unveil new areas of the world (including, eventually, the Americas), but none of them quite measure up to the personal, religious, and political drama that this first trilogy achieved. These books set a new standard for me as a reader and writer when I first encountered them in my twenties, and after several readings over the last decade, they continue to teach me more about how to intertwine sociological exposition, fast-paced genre writing, and deep character development.