I wish The Book of Ti'ana was more popular, in part because this is a fascinating novel, but also because it's a story whose flaws are worth thinking about.
Functioning as a prequel to The Book of Atrus, Ti'ana details the events leading to the destruction of the utopian city of D'ni (the ruined setting of the earlier novel). The main storyline follows a woman from Earth, Anna, who after befriending a D'ni official named Aitrus, begins studying the D'ni "Art" of using an ancient written language to open portals between parallel universes. Yet as Anna masters the Art's unlimited power, her presence in this city also triggers a bigoted movement calling for her exile. Worse, at the head of this movement is no one less than one of Aitrus's closest friends--a prominent D'ni politician named Veovis who begins dedicating his life to upholding an authoritarian view of D'ni tradition.
The strongest elements of The Book of Ti'ana are by far those early chapters depicting the hidden bigotry of D'ni society. As the story opens, D'ni is portrayed as a thriving utopia, but as Aitrus and Anna grow closer, both characters realize how this city is permanently marred by Veovis's conservatism. This realization in turn ultimately drives Aitrus to cut ties with his former friend, now that he has seen the violent ideology which people like Veovis conceal with their wealth and status.
Unfortunately, this plot is hampered by the book's ending, which in the latter chapters pivots away from the novel's social themes, and instead focuses on the supposed tragedy of Aitrus and Veovis's lost friendship. That is, as Veovis becomes increasingly enraged at Aitrus for choosing not to expel Anna from this city (ultimately plotting the destruction of the entire D'ni civilization in retaliation), the book seems to pin the blame for Veovis's actions not on Veovis himself, but (due to how it is her existence that has enraged him so much) Anna. At its most bizarre moments, The Book of Ti'ana appears poised to construct an inverted version of the tolerance paradox--a distorted parable arguing that we should actually be accommodating of bigotry, because otherwise bigots like Veovis will destroy everything.
Still, I think the themes which this story is trying to explore with regards to the dangers of traditionalism are worth following, even if they are explored imperfectly. I see The Book of Ti'ana as a really fascinating case study in the problems that can arise when well-meaning (if not perhaps misinformed) authors attempt to depict fascism.
I've written a longer review of this book on my blog, so I'll link to that below. Just be warned that I get into plot spoilers.
erichendel.blogspot.com/2024/07/review-myst-book-of-tiana.html