The Black Garden by Thomas de Waal (2003) — covers the Nagorno-Karabakh conflict but provides essential context for understanding post-Soviet Central Asia generally, including the ethnic and political dynamics that shaped Tajikistan's own civil war of the 1990s.
Empires of the Silk Road by Christopher Beckwith (2009) — an ambitious history of the steppe peoples and the Silk Road civilizations that made Central Asia what it is. Dense but rewarding; Tajikistan's Sogdian heritage is central to the story.
The Poet and the Tsar by Robert Finn (2002) — traces the figure of Rudaki, the 10th-century poet whose work defines classical Tajik literature, and his relationship with the Samanid court at Bukhara. The Samanid Empire was the last Persian-speaking dynasty before the Turkic and Mongol conquests, and its legacy haunts Tajik cultural identity.
Among the Mountains by Wilfred Thesiger — Thesiger traveled through the Afghanistan-Tajikistan border region; his accounts of the Wakhan Corridor and the people on both sides of the Amu Darya illuminate a world that still exists, barely.