Jamilia by Chingiz Aitmatov. The short novel that made Aitmatov's name internationally — a love story set in the Kyrgyz countryside during World War II. Louis Aragon called it "the most beautiful love story in the world".
The Day Lasts More Than a Hundred Years by Chingiz Aitmatov. Aitmatov's masterpiece, weaving together Soviet space programmes, central Asian folklore, and the daily life of a small railway station in the Kazakh steppe. The single book that does most to explain how a literate Soviet-era Central Asian thought about the world.
Murder in Samarkand by Craig Murray. Not about Kyrgyzstan, but the memoir of a British ambassador who fell foul of post-Soviet Central Asian dictatorship. Required reading for understanding the region's politics in the 2000s.
Apples are from Kazakhstan: The Land that Disappeared by Christopher Robbins. A wide-ranging travel book that takes in much of Central Asia, including Kyrgyzstan, written with affection and a sharp eye for the region's contradictions.
Eurasian Crossroads: A History of Xinjiang by James A. Millward. Heavy academic history of the great Silk Road region just over the mountains from Kyrgyzstan, useful background for understanding how the modern Kyrgyz state emerged.