The Russia House (en Inglés) - John Le Carré

Barley Blair is not a Service man: he is a small-time publisher, a self-destructive soul whose only loves are whisky and jazz. But it was Barley who, one drunken night at a dacha in Peredelkino during the Moscow Book Fair, was befriended by a high-ranking Soviet scientist who could be the greatest asset to the West since perestroika began, and made a promise. Nearly a year later, his drunken promise returns to haunt him. A reluctant Barley is quickly trained by British Intelligence and sent to Moscow to liaise with a go-between, the beautiful Katya. Both are lonely and disillusioned. Each is increasingly certain that if the human race is to have any future, all must betray their countries ...In his first post-glasnost spy novel, le Carre captures the effect of a slow and uncertain thaw on ordinary people and on the shadowy puppet-masters who command them.