Luben Markov lives in a house of memory. The coffee table in the upstairs living room is strewn with letters, newspaper clippings, typewritten manuscripts and court decisions; video and audio recordings are stashed in the cabinets of an antique sideboard; bulky ring binders, organized by year, line one of the walls in the room next door; along a staircase, several wall-mounted shelves buckle under the weight of books on communism, totalitarianism and Soviet-era intelligence services.
A tall, 70-year-old retiree with grizzled hair and large spectacles, Luben lives alone with a shaggy shepherd dog on the old family property in Knyazhevo, a rural suburb of Sofia, Bulgaria’s capital. It was here, at the foot of Vitosha Mountain, that his cousin, the writer Georgi Markov, grew up—and where, in 1969, Georgi came…