The Towers Of The Sunset by L.E. Modesitt Jr.

In a world governed by the opposing forces of Order and Chaos, an experienced leader steeped in the traditions of Order struggles to preserve his people and the hard-won stability of their civilization as technological change, political ambition, and rising unrest threaten to overturn the old balance; navigating treacherous alliances, family obligations, and battlefield crises, he must make pragmatic and often painful choices to protect knowledge, uphold duty, and guide his realm through a dangerous era of transition.

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